采用高温固相法在1 050℃下烧结，制备了LiCoO₂低浓度梯度改性样品，分别为LiF掺杂包覆（LCOLF、LCO@LF）和MgF₂掺杂包覆（LCOMF、LCO@MF）。通过光电子能谱、透射电子显微镜和电化学技术等表征方法，对比分析材料形貌及电化学性能。结果表明，体相掺杂复合电极中，LCOLF热重测试显示出最优热稳定性，LCOMF晶体中（003）和（104）晶面间距收缩；45℃下1C倍率循环70圈后，LCOLF和LCOMF比容量分别为141.45和166.98 mAh·g^-1，循环性能优于LiCoO₂。表面包覆复合电极中，LCO@LF和LCO@MF晶粒表面光洁且晶格氧键价都向更高结合能方向增强；LCO@MF构建了坚实且紧密的包覆层，循环70圈后，放电比容量和容量保持率分别为183 mAh·g^-1和91.26%（LCO@LF分别为154.38 mAh·g^-1和77.54%），循环性能显著优于体相掺杂。

Malignant tumours always threaten human health. For tumour diagnosis, positron emission tomography (PET) is the most sensitive and advanced imaging technique by radiotracers, such as radioactive ¹⁸F, ¹¹C, ⁶⁴Cu, ⁶⁸Ga, and ⁸⁹Zr. Among the radiotracers, the radioactive ¹⁸F-labelled chemical agent as PET probes plays a predominant role in monitoring, detecting, treating, and predicting tumours due to its perfect half-life. In this paper, the ¹⁸F-labelled chemical materials as PET probes are systematically summarized. First, we introduce various radionuclides of PET and elaborate on the mechanism of PET imaging. It highlights the ¹⁸F-labelled chemical agents used as PET probes, including [¹⁸F]-2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]-FDG), ¹⁸F-labelled amino acids, ¹⁸F-labelled nucleic acids, ¹⁸F-labelled receptors, 18F-labelled reporter genes, and ¹⁸F-labelled hypoxia agents. In addition, some PET probes with metal as a supplementary element are introduced briefly. Meanwhile, the ¹⁸F-labelled nanoparticles for the PET probe and the multi-modality imaging probe are summarized in detail. The approach and strategies for the fabrication of ¹⁸F-labelled PET probes are also described briefly. The future development of the PET probe is also prospected. The development and application of ¹⁸F-labelled PET probes will expand our knowledge and shed light on the diagnosis and theranostics of tumours.