Citation: Yuling Liu, Tianqi Yang, Taotao Zeng, Hao He, Min Jiang, Zeyan Zhou, Yonggang Wang. Copper-induced framework distortion in Na₂FeP₂O₇ cathode enables ultra-high rate and ultrastable sodium-ion batteries[J]. Chinese Chemical Letters, ;2026, 37(8): 112416. doi: 10.1016/j.cclet.2026.112416 shu

Copper-induced framework distortion in Na₂FeP₂O₇ cathode enables ultra-high rate and ultrastable sodium-ion batteries

Yuling Liu ^a ,
Tianqi Yang ^d ,
Taotao Zeng ^{a, b, *,} ,
Hao He ^{a, *,} ,
Min Jiang ^d ,
Zeyan Zhou ^{c, *,} ,
Yonggang Wang ^{b, *,}

a.
College of Materials Science and Engineering, Changsha University of Science & Technology, Changsha 410114, China
b.
Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, Shanghai 200433, China
c.
College of Materials Science and Engineering, Hunan University, Changsha 410082, China
d.
Department of Physics, City University of Hong Kong, Hong Kong 999077, China

Received Date: 1 December 2025
Revised Date: 11 January 2026
Accepted Date: 15 January 2026
Available Online: 15 January 2026

Figures(5)

The iron-based pyrophosphate Na₂FeP₂O₇ (NFPO) exhibits remarkable advantages including economic viability, exceptional structural stability, and outstanding safety characteristics. Nevertheless, the widespread implementation is fundamentally constrained by its poor inherent electronic conductivity and inadequate Na⁺ transport kinetics. This work employs a Cu doping strategy to achieve systematic electrochemical optimization through inducing local lattice distortions. The optimized Na₂Fe_0.97Cu_0.03P₂O₇@C (0.03Cu-NFPO@C) composite delivers an impressive specific capacity of 91.32 mAh/g at 0.05 C and exhibits remarkable rate capability of 39.07 mAh/g at 50 C, whereas pristine NFPO@C merely provides 24.12 mAh/g. Furthermore, 0.03Cu-NFPO@C demonstrates extraordinary cycling stability, retaining 86.40% capacity after 12, 000 cycles at 40 C. Structural characterization through in-situ X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) confirms that Cu doping effectively stabilizes the crystal framework, modifies Fe coordination environments and shortens Fe-O bond lengths. Theory calculations demonstrate that Cu doping reduces the band gap and lowers Na⁺ diffusion barriers, thereby optimizing intrinsic electronic conductivity and ion transport kinetics. This study introduces an innovative methodology for designing polyanionic cathodes, accelerating the commercialization of sodium-ion batteries for grid-scale energy storage.
- Sodium-ion batteries,
- Cathode material,
- Sodium iron pyrophosphate,
- Cu doping,
- Electronic conductivity
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通讯作者: 陈斌, bchen63@163.com

Copper-induced framework distortion in Na₂FeP₂O₇ cathode enables ultra-high rate and ultrastable sodium-ion batteries