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2025 Volume 41 Issue 1
2025, 41(1): 100004
doi: 10.3866/PKU.WHXB202309019
Abstract:
Current commercialized lithium ion batteries generally suffer from safety issues due to using flammable organic liquid electrolytes. All-solid-state lithium batteries employing solid electrolytes instead of organic liquid electrolytes and separators possess the advantages of both good safety and high energy density, which is expected to be the most promising energy storage devices for the next generation electric vehicles and smart grid. Sulfide solid electrolytes are regarded as crucial components for all-solid-state rechargeable batteries for the merits of their high room temperature ionic conductivities that approaches or exceeds liquid organic electrolytes and excellent mechanical ductility. The preparation methods of sulfide solid electrolytes are mainly divided into three categories, i.e. solid-state sintering, ball milling and liquid-phase method. However, solid-state sintering and ball milling are time-consuming accompanied by high energy consumption. At the same time, the synthesized electrolyte particles are large in size, which seriously limits the practical application of sulfide electrolytes. In contrast, the liquid-phase method, using organic solvents as the medium, can synthesize sulfide solid electrolytes with controlled particle sizes, which is a simple and time-saving process and more suitable for large-scale production. In this review, we begin by introducing the crystal structures and ion transport mechanisms of major sulfide electrolytes including Li2S-P2S5 binary sulfide solid electrolytes, Li10GeP2S12 and Li6PS5X (X = Cl, Br, I) ternary systems, and summarize the progress of sulfide solid electrolytes prepared by liquid phase method in recent years. Based on the solubility state of the reagents in the solvent, the liquid-phase synthesis of sulfide electrolytes can be categorized into suspension type, solution type and mixed type, and their reaction mechanisms are discussed separately. Subsequently, we summarize the effect of solvents on the properties of liquid-phase synthesized sulfide electrolytes, such as purity, morphology, crystallinity and ionic conductivity. In addition, the application of liquid-phase synthesized sulfide solid electrolytes for all-solid-state lithium batteries is presented from six aspects: sulfide electrolytes coated on active materials, electrolyte-active material composites, electrolyte injection into porous electrodes, interfacial modification at solid-solid contact triple-interfaces within electrode layers, electrolyte elemental doping and electrolyte film preparation, which demonstrates the superior scalability of the liquid-phase method and the diverse application prospects. Finally, according to the current research status of the sulfide solid electrolytes synthesized by liquid phase method, the advantages and limitations of the liquid phase synthesis of sulfide solid electrolytes are also analyzed, providing the development direction for the liquid phase synthesized sulfide solid electrolyte for all-solid-state lithium batteries in future.![]()
Current commercialized lithium ion batteries generally suffer from safety issues due to using flammable organic liquid electrolytes. All-solid-state lithium batteries employing solid electrolytes instead of organic liquid electrolytes and separators possess the advantages of both good safety and high energy density, which is expected to be the most promising energy storage devices for the next generation electric vehicles and smart grid. Sulfide solid electrolytes are regarded as crucial components for all-solid-state rechargeable batteries for the merits of their high room temperature ionic conductivities that approaches or exceeds liquid organic electrolytes and excellent mechanical ductility. The preparation methods of sulfide solid electrolytes are mainly divided into three categories, i.e. solid-state sintering, ball milling and liquid-phase method. However, solid-state sintering and ball milling are time-consuming accompanied by high energy consumption. At the same time, the synthesized electrolyte particles are large in size, which seriously limits the practical application of sulfide electrolytes. In contrast, the liquid-phase method, using organic solvents as the medium, can synthesize sulfide solid electrolytes with controlled particle sizes, which is a simple and time-saving process and more suitable for large-scale production. In this review, we begin by introducing the crystal structures and ion transport mechanisms of major sulfide electrolytes including Li2S-P2S5 binary sulfide solid electrolytes, Li10GeP2S12 and Li6PS5X (X = Cl, Br, I) ternary systems, and summarize the progress of sulfide solid electrolytes prepared by liquid phase method in recent years. Based on the solubility state of the reagents in the solvent, the liquid-phase synthesis of sulfide electrolytes can be categorized into suspension type, solution type and mixed type, and their reaction mechanisms are discussed separately. Subsequently, we summarize the effect of solvents on the properties of liquid-phase synthesized sulfide electrolytes, such as purity, morphology, crystallinity and ionic conductivity. In addition, the application of liquid-phase synthesized sulfide solid electrolytes for all-solid-state lithium batteries is presented from six aspects: sulfide electrolytes coated on active materials, electrolyte-active material composites, electrolyte injection into porous electrodes, interfacial modification at solid-solid contact triple-interfaces within electrode layers, electrolyte elemental doping and electrolyte film preparation, which demonstrates the superior scalability of the liquid-phase method and the diverse application prospects. Finally, according to the current research status of the sulfide solid electrolytes synthesized by liquid phase method, the advantages and limitations of the liquid phase synthesis of sulfide solid electrolytes are also analyzed, providing the development direction for the liquid phase synthesized sulfide solid electrolyte for all-solid-state lithium batteries in future.
2025, 41(1): 100009
doi: 10.3866/PKU.WHXB202404042
Abstract:
Nickel cobalt manganese-based cathode materials (NCMs) have emerged as key representatives in lithium-ion power batteries due to their high energy and power densities. The layered crystal structure of NCMs undergoes topological transformation from hydroxide precursor materials crystals. Therefore, the electrochemical performance of NCMs is directly influenced by factors such as particle size distribution, sphericity, and morphology of primary and secondary particles of precursor materials. The co-precipitation method is widely employed in laboratory and industry to produce batch precursor materials with uniform composition, adjustable structure, and high tap density. However, the co-precipitation process involves numerous adjustable parameters, and there exist significant variations in the growth parameters of precursors with different compositions and even different particle sizes within the same composition, resulting in poor characteristics such as bad sphericity, poor crystallinity, and low tap density. Addressing the need for controlled co-precipitation of nickel cobalt manganese-based precursors, this review began with an exposition on the basic theory of co-precipitation, elaborating on the principle of regulating precipitation rate and uniformity of Ni-Co-Mn elements through complexation. The heterogeneous nucleation (growth), homogeneous nucleation (independent nucleation), and the coexistence of two nucleation modes induced by different supersaturation of precipitates were explained according to different nucleation dominant modes. The growth theory of hexagonal nanosheet and rod-shaped primary particles was introduced from the perspective of preferential growth, while analyzing the growth pattern of secondary particle aggregates in terms of minimizing surface energy and following dissolving-recrystallization. From the viewpoint of practical production and application, this study comprehensively investigated adjustable parameters of the co-precipitation reaction process, including pH value, total ammonia concentration, solid content, reaction time, reaction temperature, base solution volume, stirring rate, tank reactor structure, aging time, reaction atmosphere, and drying atmosphere. The impact of varying each parameter from low to high on the nucleation of the co-precipitation reaction process and the physicochemical properties of precursors was extensively discussed. This systematic review contributes to a deeper understanding of the precursor nucleation process, facilitating the further development of relevant theories towards the advancement of products such as lithium-rich manganese-based precursors, single crystal precursors, and radially arranged texture precursors.![]()
Nickel cobalt manganese-based cathode materials (NCMs) have emerged as key representatives in lithium-ion power batteries due to their high energy and power densities. The layered crystal structure of NCMs undergoes topological transformation from hydroxide precursor materials crystals. Therefore, the electrochemical performance of NCMs is directly influenced by factors such as particle size distribution, sphericity, and morphology of primary and secondary particles of precursor materials. The co-precipitation method is widely employed in laboratory and industry to produce batch precursor materials with uniform composition, adjustable structure, and high tap density. However, the co-precipitation process involves numerous adjustable parameters, and there exist significant variations in the growth parameters of precursors with different compositions and even different particle sizes within the same composition, resulting in poor characteristics such as bad sphericity, poor crystallinity, and low tap density. Addressing the need for controlled co-precipitation of nickel cobalt manganese-based precursors, this review began with an exposition on the basic theory of co-precipitation, elaborating on the principle of regulating precipitation rate and uniformity of Ni-Co-Mn elements through complexation. The heterogeneous nucleation (growth), homogeneous nucleation (independent nucleation), and the coexistence of two nucleation modes induced by different supersaturation of precipitates were explained according to different nucleation dominant modes. The growth theory of hexagonal nanosheet and rod-shaped primary particles was introduced from the perspective of preferential growth, while analyzing the growth pattern of secondary particle aggregates in terms of minimizing surface energy and following dissolving-recrystallization. From the viewpoint of practical production and application, this study comprehensively investigated adjustable parameters of the co-precipitation reaction process, including pH value, total ammonia concentration, solid content, reaction time, reaction temperature, base solution volume, stirring rate, tank reactor structure, aging time, reaction atmosphere, and drying atmosphere. The impact of varying each parameter from low to high on the nucleation of the co-precipitation reaction process and the physicochemical properties of precursors was extensively discussed. This systematic review contributes to a deeper understanding of the precursor nucleation process, facilitating the further development of relevant theories towards the advancement of products such as lithium-rich manganese-based precursors, single crystal precursors, and radially arranged texture precursors.
2025, 41(1): 100006
doi: 10.3866/PKU.WHXB202309042
Abstract:
Since the initial report on multiple resonance thermally activated delayed fluorescence (MR-TADF) molecules, their narrow band emissions, high quantum yields and other characteristics have consistently fueled research interest in the realm of organic electronics, particularly organic light emitting diodes (OLED). These molecules swiftly ascended to the forefront of research, serving as a pivotal focus, giving rise to numerous high-performance devices and meticulously crafted molecules. Devices featuring MR-TADF molecules as the luminescent core continually redefine our comprehension of OLED, with some employing hyperfluorescence technology attaining peak performance in specific photochromic domains today. Presently, with the escalating demand for ultra-high-resolution displays, the international telecommunication union (ITU) has unveiled the next generation color gamut standard, BT.2020. This standard delineates the broadest display color gamut, mandating monochromatic primary color wavelengths of 467, 532, and 630 nm, constituting an exceptionally extensive color gamut. Simultaneously, achieving high-resolution displays with such an expansive color gamut imposes unprecedentedly stringent requirements on the color purity of device elements. Consequently, it imposes a formidable color purity target for display technology. In the past, traditional fluorescent materials struggled to meet these demands. The advent of BT.2020, however, has presented new opportunities for the advancement of MR-TADF molecules, leading to a surge in popularity in this field. In recent years, with copious research and practical applications, the MR-TADF molecular family has undergone rapid evolution. Nevertheless, discussions and summaries primarily centered on the field's development, with limited focus on molecular design strategies. This deficiency hinders adequate reference for researchers entering the field. Consequently, this article expounds upon the design principles of select MR-TADF molecules reported in the past three years. It delves into aspects such as the X-π-X principle, fast reverse intersystem crossing processes, narrow-band emission, and high oscillator strength. Additionally, it posits future design directions, including the incorporation of non-traditional structures into the MR-TADF domain. Finally, the article offers suggestions for the prospective development and industrialization of the MR-TADF field.![]()
Since the initial report on multiple resonance thermally activated delayed fluorescence (MR-TADF) molecules, their narrow band emissions, high quantum yields and other characteristics have consistently fueled research interest in the realm of organic electronics, particularly organic light emitting diodes (OLED). These molecules swiftly ascended to the forefront of research, serving as a pivotal focus, giving rise to numerous high-performance devices and meticulously crafted molecules. Devices featuring MR-TADF molecules as the luminescent core continually redefine our comprehension of OLED, with some employing hyperfluorescence technology attaining peak performance in specific photochromic domains today. Presently, with the escalating demand for ultra-high-resolution displays, the international telecommunication union (ITU) has unveiled the next generation color gamut standard, BT.2020. This standard delineates the broadest display color gamut, mandating monochromatic primary color wavelengths of 467, 532, and 630 nm, constituting an exceptionally extensive color gamut. Simultaneously, achieving high-resolution displays with such an expansive color gamut imposes unprecedentedly stringent requirements on the color purity of device elements. Consequently, it imposes a formidable color purity target for display technology. In the past, traditional fluorescent materials struggled to meet these demands. The advent of BT.2020, however, has presented new opportunities for the advancement of MR-TADF molecules, leading to a surge in popularity in this field. In recent years, with copious research and practical applications, the MR-TADF molecular family has undergone rapid evolution. Nevertheless, discussions and summaries primarily centered on the field's development, with limited focus on molecular design strategies. This deficiency hinders adequate reference for researchers entering the field. Consequently, this article expounds upon the design principles of select MR-TADF molecules reported in the past three years. It delves into aspects such as the X-π-X principle, fast reverse intersystem crossing processes, narrow-band emission, and high oscillator strength. Additionally, it posits future design directions, including the incorporation of non-traditional structures into the MR-TADF domain. Finally, the article offers suggestions for the prospective development and industrialization of the MR-TADF field.
2025, 41(1): 100001
doi: 10.3866/PKU.WHXB202308032
Abstract:
Developing hydrogen energy to replace carbon-rich fossil fuels is the future direction of energy technology, but there is still a lack of safe and efficient hydrogen storage technology. Hydrogen storage in solid medium is a relatively safe way to store hydrogen, among which magnesium hydride (MgH2) is one of the most promising solid hydrogen storage materials. MgH2 has the advantages of high hydrogen storage density, low cost and good reversibility of hydrogen absorption and release. However, improving its poor thermodynamic and slow kinetic characteristics are still challenging. Catalysts derived from polyoxometalates have been successfully used for catalyzing hydrogen evolution reaction, oxidation of organic compounds, desulfurization reaction, and so on. However, these catalysts have not been applied to the hydrogen storage materials yet. In this paper, H3PW12O40 is selected as a representative of polyoxometalates and its catalytic effect on hydrogen storage is studied. MgH2-xH3PW12O40 (x = 7%, 10%, 13%, mass percentage) and pure MgH2 samples are prepared by mechanical ball milling method. Among them, MgH2-10H3PW12O40 exhibits the optimal performance in both kinetic characteristic and hydrogen storage capacity. It can rapidly absorb 6.25% hydrogen within 1 min at 250 ℃ and release 6.54% hydrogen within 15 min at 300 ℃, while ball-milled MgH2 only releases 1.2% hydrogen within 30 min at 300 ℃. At the same time, the activation energy of the composite decreases to 106.08 kJ∙mol−1, which is 46.23 kJ∙mol−1 lower than MgH2. The catalytic effect of H3PW12O40 on the hydrogen storage properties of MgH2 mainly comes from three aspects. Firstly, the addition of H3PW12O40 helps to avoid the agglomeration of MgH2 during the ball milling process, which makes the MgH2 particles become smaller after ball milling, thus increasing the specific surface area of the interaction with hydrogen. Secondly, the addition of H3PW12O40 makes MgH2 produce a large number of defects and lattice distortion during ball milling, which provides more channels for hydrogen diffusion. Thirdly, the catalytic components of WO3 and W are in situ formed during the ball milling process. They can be used as active components to accelerate the electron migration process, which promotes the cleavage of the Mg―H bond and the adsorption and dissociation of hydrogen.![]()
Developing hydrogen energy to replace carbon-rich fossil fuels is the future direction of energy technology, but there is still a lack of safe and efficient hydrogen storage technology. Hydrogen storage in solid medium is a relatively safe way to store hydrogen, among which magnesium hydride (MgH2) is one of the most promising solid hydrogen storage materials. MgH2 has the advantages of high hydrogen storage density, low cost and good reversibility of hydrogen absorption and release. However, improving its poor thermodynamic and slow kinetic characteristics are still challenging. Catalysts derived from polyoxometalates have been successfully used for catalyzing hydrogen evolution reaction, oxidation of organic compounds, desulfurization reaction, and so on. However, these catalysts have not been applied to the hydrogen storage materials yet. In this paper, H3PW12O40 is selected as a representative of polyoxometalates and its catalytic effect on hydrogen storage is studied. MgH2-xH3PW12O40 (x = 7%, 10%, 13%, mass percentage) and pure MgH2 samples are prepared by mechanical ball milling method. Among them, MgH2-10H3PW12O40 exhibits the optimal performance in both kinetic characteristic and hydrogen storage capacity. It can rapidly absorb 6.25% hydrogen within 1 min at 250 ℃ and release 6.54% hydrogen within 15 min at 300 ℃, while ball-milled MgH2 only releases 1.2% hydrogen within 30 min at 300 ℃. At the same time, the activation energy of the composite decreases to 106.08 kJ∙mol−1, which is 46.23 kJ∙mol−1 lower than MgH2. The catalytic effect of H3PW12O40 on the hydrogen storage properties of MgH2 mainly comes from three aspects. Firstly, the addition of H3PW12O40 helps to avoid the agglomeration of MgH2 during the ball milling process, which makes the MgH2 particles become smaller after ball milling, thus increasing the specific surface area of the interaction with hydrogen. Secondly, the addition of H3PW12O40 makes MgH2 produce a large number of defects and lattice distortion during ball milling, which provides more channels for hydrogen diffusion. Thirdly, the catalytic components of WO3 and W are in situ formed during the ball milling process. They can be used as active components to accelerate the electron migration process, which promotes the cleavage of the Mg―H bond and the adsorption and dissociation of hydrogen.
2025, 41(1): 100002
doi: 10.3866/PKU.WHXB202309002
Abstract:
The concentration of carbon dioxide (CO2) in the atmosphere is progressively increasing due to industrial development, leading to environmental concerns such as the greenhouse effect. Consequently, it is crucial to decrease dependence on the fossil fuels and mitigate the CO2 emissions. Photothermocatalysis technology facilitates the conversion of light energy into heat energy on the surface of catalysts, thereby driving chemical reactions. This catalytic approach effectively harnesses ample solar energy, consequently reducing non-renewable energy consumption. Solar-driven CO2 methanation is an important route to simultaneously mitigate excessive carbon emissions and produce fuels. Layered double hydroxides (LDH) can be reduced at high temperature in a reductive atmosphere of a hydrogen/argon (H2/Ar) mixture to prepare metal-loaded oxide (MO) catalysts, which are widely used in CO2 hydrogenation reactions as excellent photothermal catalysts. However, there is limited study on how the interlayer anion type of LDH affects the activity of CO2 methanation. Herein, a series of LDH precursors, intercalated with various anions, were synthesized using a co-precipitation method. The LDH precursors were reduced in a H2/Ar atmosphere to acquire a group of nickel (Ni) loaded on alumina (Al2O3) catalysts, referred to as NiAl-x-MO (x = CO3, NO3, Cl, and SO4, which represents carbonate, nitrate, chloride, and sulfate anions, respectively). Energy dispersive spectrometer (EDS) elemental mapping and X-ray photoelectron spectroscopy (XPS) results revealed the presence of nitrogen (N), chlorine (Cl), and sulfur (S) species on the surfaces of NiAl-NO3-MO, NiAl-Cl-MO, and NiAl-SO4-MO catalysts, respectively. Photothermocatalytic tests were conducted on the catalysts to assess the potential influence of the residual species on CO2 methanation. Among them, the NiAl-CO3-MO catalyst demonstrated a CO2 conversion of 50.1%, methane (CH4) selectivity of 99.9%, along with a CH4 production rate of 94.4 mmol∙g−1∙h−1. The performance of the NiAl-NO3-MO catalyst was found to be comparable to that of the NiAl-CO3-MO catalyst. In contrast, the CO2 methanation activity of the NiAl-Cl-MO and NiAl-SO4-MO catalysts were negligible. CO2 temperature programmed desorption (CO2-TPD) analysis demonstrated that the presence of N, Cl, and S species had a negligible effect on the adsorption of CO2. H2 temperature programmed desorption (H2-TPD) and density functional theory (DFT) results suggested that the strong coordination bond between residual Cl or S species and metallic Ni impeded the absorption and activation of H2, which was responsible for the low CO2 conversion. Hence, the significant role of the interlayer anion in LDH should be preferentially considered when designing LDH-derived catalysts, especially the Ni-based catalysts for hydrogenation reactions.![]()
The concentration of carbon dioxide (CO2) in the atmosphere is progressively increasing due to industrial development, leading to environmental concerns such as the greenhouse effect. Consequently, it is crucial to decrease dependence on the fossil fuels and mitigate the CO2 emissions. Photothermocatalysis technology facilitates the conversion of light energy into heat energy on the surface of catalysts, thereby driving chemical reactions. This catalytic approach effectively harnesses ample solar energy, consequently reducing non-renewable energy consumption. Solar-driven CO2 methanation is an important route to simultaneously mitigate excessive carbon emissions and produce fuels. Layered double hydroxides (LDH) can be reduced at high temperature in a reductive atmosphere of a hydrogen/argon (H2/Ar) mixture to prepare metal-loaded oxide (MO) catalysts, which are widely used in CO2 hydrogenation reactions as excellent photothermal catalysts. However, there is limited study on how the interlayer anion type of LDH affects the activity of CO2 methanation. Herein, a series of LDH precursors, intercalated with various anions, were synthesized using a co-precipitation method. The LDH precursors were reduced in a H2/Ar atmosphere to acquire a group of nickel (Ni) loaded on alumina (Al2O3) catalysts, referred to as NiAl-x-MO (x = CO3, NO3, Cl, and SO4, which represents carbonate, nitrate, chloride, and sulfate anions, respectively). Energy dispersive spectrometer (EDS) elemental mapping and X-ray photoelectron spectroscopy (XPS) results revealed the presence of nitrogen (N), chlorine (Cl), and sulfur (S) species on the surfaces of NiAl-NO3-MO, NiAl-Cl-MO, and NiAl-SO4-MO catalysts, respectively. Photothermocatalytic tests were conducted on the catalysts to assess the potential influence of the residual species on CO2 methanation. Among them, the NiAl-CO3-MO catalyst demonstrated a CO2 conversion of 50.1%, methane (CH4) selectivity of 99.9%, along with a CH4 production rate of 94.4 mmol∙g−1∙h−1. The performance of the NiAl-NO3-MO catalyst was found to be comparable to that of the NiAl-CO3-MO catalyst. In contrast, the CO2 methanation activity of the NiAl-Cl-MO and NiAl-SO4-MO catalysts were negligible. CO2 temperature programmed desorption (CO2-TPD) analysis demonstrated that the presence of N, Cl, and S species had a negligible effect on the adsorption of CO2. H2 temperature programmed desorption (H2-TPD) and density functional theory (DFT) results suggested that the strong coordination bond between residual Cl or S species and metallic Ni impeded the absorption and activation of H2, which was responsible for the low CO2 conversion. Hence, the significant role of the interlayer anion in LDH should be preferentially considered when designing LDH-derived catalysts, especially the Ni-based catalysts for hydrogenation reactions.
2025, 41(1): 100003
doi: 10.3866/PKU.WHXB202309003
Abstract:
Aqueous zinc ion batteries (ZIBs) are regarded as one of the most promising energy storage systems due to their reliable safety, low cost, high volumetric capacity, and environmental friendliness. However, the utilization of Zn metal anode in aqueous electrolyte commonly encounters complex water-induced side reactions and uncontrollable dendrite growth issues. Constructing a protective layer on the surface of Zn anode is an effective strategy to alleviate side reactions and dendrite growth, achieving the stable operation of ZIBs with prolonged cycling life. However, the utilization of protective layers will increase interfacial resistance and result in high polarization in most cases. Thus, developing a desirable artificial protective layer with high ion migration kinetics is a significant task, enabling a fast Zn2+ ion flux for homogeneous deposition with low polarization. Considering that porous aluminosilicate zeolite with a low Si/Al ratio can accommodate abundant framework-associated cations as charge carriers for conduction, herein, we prepared an oriented protective layer on the Zn anode using Zn-ion-exchanged Q zeolite with BPH topology (ZnQ@Zn), achieving a stable Zn anode with high ion migration kinetics. The ZnQ zeolite plates parallelly lay on the surface of Zn foil with the c axis normal to the substrate plane. The three-dimensional ordered channels and the oriented arrangement of ZnQ zeolite plates provide facile ion migration pathways for Zn2+ ions, and the coordination of framework-associated Zn2+ ions with water in zeolite channels also enables fast ion conduction kinetics and high corrosion resistance. Therefore, ZnQ@Zn exhibits enhanced ion conduction kinetics with reduced energy barriers for desolvation, charge transfer, and diffusion processes, resulting in a uniform ion flux to suppress dendrite growth. Consequently, the ZnQ@Zn symmetric cell displays an ultra-low voltage hysteresis of 27 mV with a long lifespan of over 1100 h at 1 mA∙cm−2 and 1 mAh∙cm−2. Moreover, the ZnQ@Zn//NaV3O8·1.5H2O full cell delivers a superior long-term cycling performance with a high capacity retention of 96% after 1800 cycles at 8 A∙g−1. This work provides a new sight for constructing protective layers with fast ion migration kinetics to achieve high-stable Zn anodes, and extends the application of zeolite-based ion-conductive materials in energy storage devices.![]()
Aqueous zinc ion batteries (ZIBs) are regarded as one of the most promising energy storage systems due to their reliable safety, low cost, high volumetric capacity, and environmental friendliness. However, the utilization of Zn metal anode in aqueous electrolyte commonly encounters complex water-induced side reactions and uncontrollable dendrite growth issues. Constructing a protective layer on the surface of Zn anode is an effective strategy to alleviate side reactions and dendrite growth, achieving the stable operation of ZIBs with prolonged cycling life. However, the utilization of protective layers will increase interfacial resistance and result in high polarization in most cases. Thus, developing a desirable artificial protective layer with high ion migration kinetics is a significant task, enabling a fast Zn2+ ion flux for homogeneous deposition with low polarization. Considering that porous aluminosilicate zeolite with a low Si/Al ratio can accommodate abundant framework-associated cations as charge carriers for conduction, herein, we prepared an oriented protective layer on the Zn anode using Zn-ion-exchanged Q zeolite with BPH topology (ZnQ@Zn), achieving a stable Zn anode with high ion migration kinetics. The ZnQ zeolite plates parallelly lay on the surface of Zn foil with the c axis normal to the substrate plane. The three-dimensional ordered channels and the oriented arrangement of ZnQ zeolite plates provide facile ion migration pathways for Zn2+ ions, and the coordination of framework-associated Zn2+ ions with water in zeolite channels also enables fast ion conduction kinetics and high corrosion resistance. Therefore, ZnQ@Zn exhibits enhanced ion conduction kinetics with reduced energy barriers for desolvation, charge transfer, and diffusion processes, resulting in a uniform ion flux to suppress dendrite growth. Consequently, the ZnQ@Zn symmetric cell displays an ultra-low voltage hysteresis of 27 mV with a long lifespan of over 1100 h at 1 mA∙cm−2 and 1 mAh∙cm−2. Moreover, the ZnQ@Zn//NaV3O8·1.5H2O full cell delivers a superior long-term cycling performance with a high capacity retention of 96% after 1800 cycles at 8 A∙g−1. This work provides a new sight for constructing protective layers with fast ion migration kinetics to achieve high-stable Zn anodes, and extends the application of zeolite-based ion-conductive materials in energy storage devices.
2025, 41(1): 100005
doi: 10.3866/PKU.WHXB202309037
Abstract:
Solid oxide cell (SOC) is a typical multi-layer thin film ceramic device consisting of oxygen electrodes, electrolytes, and hydrogen electrodes. The currently widely used structure is a single cell supported by a Ni-YSZ (Nickel-Yttria Stabilized Zirconia) hydrogen electrode, with YSZ (Yttria Stabilized Zirconia) serving as the electrolyte. This configuration achieves electrolyte filmization, while also reducing the operating temperature of the cell. However, it introduces significant diffusion impedance within the hydrogen electrode, which is considered the main reason for the electrochemical asymmetry in reversible solid oxide cell (R-SOC). This study prepared hydrogen electrodes with varying porosity and investigated the impact of diffusion impedance of hydrogen electrodes on R-SOC asymmetry. On this basis, hydrothermal in situ growth technology was employed to prepare ultra-thin and dense GDC (Gd2O3 doped CeO2) barrier layers, compared with conventional screen-printed barrier layers to explore the effect of electrolyte ohmic impedance on electrochemical asymmetry. Experimental findings revealed that the electrolyte ohmic impedance is also a significant factor affecting the electrochemical asymmetry of reversible SOC, and the synergistic mechanism of the diffusion impedance of hydrogen electrodes and the ohmic impedance of thin film electrolytes on this asymmetry was elucidated. The experimental results show that increasing the hydrogen electrode porosity and reducing the electrolyte ohmic impedance can both enhance the R-SOC performance, particularly improving SOEC electrolysis performance, and both have the effect of reducing asymmetry. At 750 ℃, 50% H2O, and ±0.3 V bias conditions, the single cell with a large-pore hydrogen electrode and a thin film barrier layer exhibited a discharge current density of 0.752 A∙cm−2 and an electrolysis current density of 0.635 A∙cm−2. Compared to the single cell with a small pore hydrogen electrode and an ordinary screen-printed barrier layer, the discharge and electrolysis performance of the cell have been improved by ~37% and ~140%, respectively. At the same time, the current density asymmetry of the cell (∆j) under these conditions was only 0.117 A∙cm−2, reduced by 58% compared to a small porosity hydrogen electrode single cell and 24% compared to a large ohmic impedance single cell. In addition, the study noted that R-SOC asymmetry increases with operating temperature and decreases with higher steam content in the fuel on the hydrogen electrode side. These findings hold significant reference value the design, preparation, and reversible operation of high-performance hydrogen electrode supported thin film electrolyte SOC single cell structures.![]()
Solid oxide cell (SOC) is a typical multi-layer thin film ceramic device consisting of oxygen electrodes, electrolytes, and hydrogen electrodes. The currently widely used structure is a single cell supported by a Ni-YSZ (Nickel-Yttria Stabilized Zirconia) hydrogen electrode, with YSZ (Yttria Stabilized Zirconia) serving as the electrolyte. This configuration achieves electrolyte filmization, while also reducing the operating temperature of the cell. However, it introduces significant diffusion impedance within the hydrogen electrode, which is considered the main reason for the electrochemical asymmetry in reversible solid oxide cell (R-SOC). This study prepared hydrogen electrodes with varying porosity and investigated the impact of diffusion impedance of hydrogen electrodes on R-SOC asymmetry. On this basis, hydrothermal in situ growth technology was employed to prepare ultra-thin and dense GDC (Gd2O3 doped CeO2) barrier layers, compared with conventional screen-printed barrier layers to explore the effect of electrolyte ohmic impedance on electrochemical asymmetry. Experimental findings revealed that the electrolyte ohmic impedance is also a significant factor affecting the electrochemical asymmetry of reversible SOC, and the synergistic mechanism of the diffusion impedance of hydrogen electrodes and the ohmic impedance of thin film electrolytes on this asymmetry was elucidated. The experimental results show that increasing the hydrogen electrode porosity and reducing the electrolyte ohmic impedance can both enhance the R-SOC performance, particularly improving SOEC electrolysis performance, and both have the effect of reducing asymmetry. At 750 ℃, 50% H2O, and ±0.3 V bias conditions, the single cell with a large-pore hydrogen electrode and a thin film barrier layer exhibited a discharge current density of 0.752 A∙cm−2 and an electrolysis current density of 0.635 A∙cm−2. Compared to the single cell with a small pore hydrogen electrode and an ordinary screen-printed barrier layer, the discharge and electrolysis performance of the cell have been improved by ~37% and ~140%, respectively. At the same time, the current density asymmetry of the cell (∆j) under these conditions was only 0.117 A∙cm−2, reduced by 58% compared to a small porosity hydrogen electrode single cell and 24% compared to a large ohmic impedance single cell. In addition, the study noted that R-SOC asymmetry increases with operating temperature and decreases with higher steam content in the fuel on the hydrogen electrode side. These findings hold significant reference value the design, preparation, and reversible operation of high-performance hydrogen electrode supported thin film electrolyte SOC single cell structures.
2025, 41(1): 100008
doi: 10.3866/PKU.WHXB202403008
Abstract:
Electrochemical nitrate reduction reaction (eNO3–RR) to synthesize NH3 is a sustainable method to convert environmental contaminants into valuables. Pd based bimetallic nanocatalysts have demonstrated great promise as efficient catalysts, yet modulating the composition and configuration to improve the catalytic performance and achieve comprehensive mechanistic understanding remains challenging. Herein, by employing two ligands with different electron functional groups, we successfully prepared two atomically precise (AgPd)27 bimetallic clusters of Ag18Pd9(C8H4F)24 (Ag18Pd9) and Ag22Pd5(C9H10O2)26 (Ag22Pd5). The two clusters possess markedly different metal core composition and configuration, where Ag18Pd9 has a sandwich metal core structure with 9 Pd atoms located in the middle layer and Ag22Pd5 has a rod-shaped metal core structure composed of the M13 configuration with 5 Pd atoms located at the center and vertices of the M13 configuration. Unexpectedly, Ag22Pd5 exhibited remarkably superior eNO3−RR performance than Ag18Pd9. Specifically, the highest Faradaic efficiency of NH3 (FENH3) and its yield rate can reach 94.42% and 1.41 mmol∙h−1∙mg−1 at −0.6 V vs. RHE for Ag22Pd5, but the largest FENH3 and NH3 yield rate is only 43.86% and 0.41 mmol∙h−1∙mg−1 at −0.5 V vs. RHE for Ag18Pd9. The in situ attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) test provides the experimental evidence of the reaction intermediates hence revealing the reaction pathway, also shows that Ag22Pd5 has stronger capability for NO3− adsorption and NH3 desorption than that of Ag18Pd9. Theoretical calculations indicate that the de-ligated clusters can expose the available AgPd bimetallic sites, synergistically serving as effective active sites and the different configurations result in significantly different catalytic activities, where the active sites in Ag22Pd5 are more favorable for NO3− adsorption and NH3 desorption to accelerate the catalytic process.![]()
Electrochemical nitrate reduction reaction (eNO3–RR) to synthesize NH3 is a sustainable method to convert environmental contaminants into valuables. Pd based bimetallic nanocatalysts have demonstrated great promise as efficient catalysts, yet modulating the composition and configuration to improve the catalytic performance and achieve comprehensive mechanistic understanding remains challenging. Herein, by employing two ligands with different electron functional groups, we successfully prepared two atomically precise (AgPd)27 bimetallic clusters of Ag18Pd9(C8H4F)24 (Ag18Pd9) and Ag22Pd5(C9H10O2)26 (Ag22Pd5). The two clusters possess markedly different metal core composition and configuration, where Ag18Pd9 has a sandwich metal core structure with 9 Pd atoms located in the middle layer and Ag22Pd5 has a rod-shaped metal core structure composed of the M13 configuration with 5 Pd atoms located at the center and vertices of the M13 configuration. Unexpectedly, Ag22Pd5 exhibited remarkably superior eNO3−RR performance than Ag18Pd9. Specifically, the highest Faradaic efficiency of NH3 (FENH3) and its yield rate can reach 94.42% and 1.41 mmol∙h−1∙mg−1 at −0.6 V vs. RHE for Ag22Pd5, but the largest FENH3 and NH3 yield rate is only 43.86% and 0.41 mmol∙h−1∙mg−1 at −0.5 V vs. RHE for Ag18Pd9. The in situ attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) test provides the experimental evidence of the reaction intermediates hence revealing the reaction pathway, also shows that Ag22Pd5 has stronger capability for NO3− adsorption and NH3 desorption than that of Ag18Pd9. Theoretical calculations indicate that the de-ligated clusters can expose the available AgPd bimetallic sites, synergistically serving as effective active sites and the different configurations result in significantly different catalytic activities, where the active sites in Ag22Pd5 are more favorable for NO3− adsorption and NH3 desorption to accelerate the catalytic process.
2025, 41(1): 100007
doi: 10.3866/PKU.WHXB202311021
Abstract:
Photomultiplication-type all-polymer photodetectors (PM-APDs) based on structure of ITO/poly(3, 4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT: PSS)/active layer/Al were developed with wide bandgap polymer poly(3-hexylthiophene) (P3HT) as donor and narrow bandgap polymer poly{2, 2'-((2Z, 2'Z)-((12, 13-bis(2-decyltetradecyl)-6-(2-ethylhexyl)-4, 8-dimethyl-6, 8, 12, 13-tetrahydro-4H-thieno[2'', 3'': 4', 5']pyrrolo[2', 3': 4, 5]pyrrolo[3, 2-g]thieno[2', 3': 4, 5]pyrrolo[3, 2-b][1, 2, 3] triazolo[4, 5-e]indole-2, 10-diyl)bis(methaneylylidene))bis(5, 5'-3-oxo-2, 3-dihydro-1H-indene-2, 1-diylidene))dimalononitrile-alt-2, 5-dithiophene} (PTz-PT) as acceptor. A series of binary PM-APDs were prepared with P3HT : PTz-PT weight ratios of 100 : 1, 100 : 4, 100 : 7, and 100 : 10. In the dark, the holes are difficultly injected from Al electrode into the active layer due to the 0.8 eV injection barriers from the work function of Al onto the highest occupied molecular orbital (HOMO) level of P3HT. The limited PTz-PT content in the active layer results in the absence of continuous electron transport channel, leading to poor electron transport ability. The photogenerated electrons are trapped in isolated PTz-PT under light illumination due to the scarce PTz-PT content in active layer and 0.84 eV difference between the lowest unoccupied molecular orbital (LUMO) of P3HT and PTz-PT. The trapped electrons near the Al electrode induce interfacial band bending for hole tunneling injection, leading to external quantum efficiency (EQE) values exceeding 100%. The optimal binary PM-APDs based on P3HT : PTz-PT (100 : 4 wt/wt) exhibit a spectral response range from 300 to 1100 nm with EQE values over 100% at -8 V bias. The EQE spectral shape of PM-APDs is determined by the distribution of trapped electrons near the Al electrode. The shape of EQE spectra is further flattened by introducing polymer poly(2-(4, 8-bis(4-(2-ethylhexyl)cyclopenta-1, 3-dien-1-yl)benzo[1, 2-b: 4, 5-b']dithiophen-2-yl)-5, 5-difluoro-10-(5-(2-hexyldecyl)thiophen-2-yl)-3, 7-dimethyl-5H-4λ4, 5λ4-dipyrrolo[1, 2-c: 2', 1'-f][1, 3, 2]diazaborinine) (PMBBDT) as the third component. A series of ternary PM-APDs with P3HT : PMBBDT : PTz-PT weight ratios of 90 : 10 : 4 and 80 : 20 : 4 were prepared. The EQE values of ternary PM-APDs are increased in the range from 420 to 600 nm and decreased in the range from 630 to 870 nm. The flatter EQE spectra of ternary PM-APDs are derived from more uniform distribution of trapped electrons near the Al electrode. Furthermore, the ternary PM-APDs exhibit higher stability under continuous illumination and applied bias than the optimal binary PM-APDs. The optimal ternary PM-APDs exhibit EQE values of 3500% at 350 nm, 1250% at 550 nm and 1500% at 900 nm under −12 V bias, as well as specific detectivity (Dshot*) values of 3.7 × 1012 Jones at 520 nm and 1.9 × 1013 Jones at 850 nm under −10 V bias. After 170 min continuous white light illumination at −10 V bias, the optimal ternary PM-APDs possess photocurrent of 87% initial value. A photoplethysmography (PPG) sensor was successfully realized by employing the optimal ternary PM-APDs to measure human heart rate (HR), with the measured HR consistent with the normal value of human HR.![]()
Photomultiplication-type all-polymer photodetectors (PM-APDs) based on structure of ITO/poly(3, 4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT: PSS)/active layer/Al were developed with wide bandgap polymer poly(3-hexylthiophene) (P3HT) as donor and narrow bandgap polymer poly{2, 2'-((2Z, 2'Z)-((12, 13-bis(2-decyltetradecyl)-6-(2-ethylhexyl)-4, 8-dimethyl-6, 8, 12, 13-tetrahydro-4H-thieno[2'', 3'': 4', 5']pyrrolo[2', 3': 4, 5]pyrrolo[3, 2-g]thieno[2', 3': 4, 5]pyrrolo[3, 2-b][1, 2, 3] triazolo[4, 5-e]indole-2, 10-diyl)bis(methaneylylidene))bis(5, 5'-3-oxo-2, 3-dihydro-1H-indene-2, 1-diylidene))dimalononitrile-alt-2, 5-dithiophene} (PTz-PT) as acceptor. A series of binary PM-APDs were prepared with P3HT : PTz-PT weight ratios of 100 : 1, 100 : 4, 100 : 7, and 100 : 10. In the dark, the holes are difficultly injected from Al electrode into the active layer due to the 0.8 eV injection barriers from the work function of Al onto the highest occupied molecular orbital (HOMO) level of P3HT. The limited PTz-PT content in the active layer results in the absence of continuous electron transport channel, leading to poor electron transport ability. The photogenerated electrons are trapped in isolated PTz-PT under light illumination due to the scarce PTz-PT content in active layer and 0.84 eV difference between the lowest unoccupied molecular orbital (LUMO) of P3HT and PTz-PT. The trapped electrons near the Al electrode induce interfacial band bending for hole tunneling injection, leading to external quantum efficiency (EQE) values exceeding 100%. The optimal binary PM-APDs based on P3HT : PTz-PT (100 : 4 wt/wt) exhibit a spectral response range from 300 to 1100 nm with EQE values over 100% at -8 V bias. The EQE spectral shape of PM-APDs is determined by the distribution of trapped electrons near the Al electrode. The shape of EQE spectra is further flattened by introducing polymer poly(2-(4, 8-bis(4-(2-ethylhexyl)cyclopenta-1, 3-dien-1-yl)benzo[1, 2-b: 4, 5-b']dithiophen-2-yl)-5, 5-difluoro-10-(5-(2-hexyldecyl)thiophen-2-yl)-3, 7-dimethyl-5H-4λ4, 5λ4-dipyrrolo[1, 2-c: 2', 1'-f][1, 3, 2]diazaborinine) (PMBBDT) as the third component. A series of ternary PM-APDs with P3HT : PMBBDT : PTz-PT weight ratios of 90 : 10 : 4 and 80 : 20 : 4 were prepared. The EQE values of ternary PM-APDs are increased in the range from 420 to 600 nm and decreased in the range from 630 to 870 nm. The flatter EQE spectra of ternary PM-APDs are derived from more uniform distribution of trapped electrons near the Al electrode. Furthermore, the ternary PM-APDs exhibit higher stability under continuous illumination and applied bias than the optimal binary PM-APDs. The optimal ternary PM-APDs exhibit EQE values of 3500% at 350 nm, 1250% at 550 nm and 1500% at 900 nm under −12 V bias, as well as specific detectivity (Dshot*) values of 3.7 × 1012 Jones at 520 nm and 1.9 × 1013 Jones at 850 nm under −10 V bias. After 170 min continuous white light illumination at −10 V bias, the optimal ternary PM-APDs possess photocurrent of 87% initial value. A photoplethysmography (PPG) sensor was successfully realized by employing the optimal ternary PM-APDs to measure human heart rate (HR), with the measured HR consistent with the normal value of human HR.
