Abstract

Synthesis method is crucial to the improved electrochemical performances of LiMnPO₄ materials with poor electronic and ionic conductivity for large-scale preparation. Here, carbon-coated LiMn_0.8Fe_0.2PO₄ materials were synthesized through a rheological phase-assisted solid-state method combined with freeze-drying. Effect of different carbon sources on the structure, morphology, and electrochemical performance of as-prepared LiMn_0.8Fe_0.2PO₄ materials was investigated. The results suggest that LiMn_0.8Fe_0.2PO₄ materials with citric acid as carbon sources show a high discharge capacity with 164, 122, and 106 mA h g⁻¹ at 0.1, 1, and 5 C, and a capacity retention of around 99.6% after 100 cycles at 1 C. This can be attributed to higher surface area, intense peak of sp² N–C=N bonds, and uniform particle distribution resulting from the rheological phase formed using citric acid as carbon sources combined with freeze-drying. The rheological phase-assisted solid-state method is a promising route for production of LiMn_0.8Fe_0.2PO₄ materials with excellent performances.

中文翻译：

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流变相辅助固相法合成碳包覆的LiMn 0.8 Fe 0.2 PO 4材料

摘要

对于大规模制备而言，合成方法对于改善电子和离子导电性差的LiMnPO ₄材料的电化学性能至关重要。在此，通过流变相辅助固态方法结合冷冻干燥合成了碳包覆的LiMn _0.8 Fe _0.2 PO ₄材料。研究了不同碳源对制备的LiMn _0.8 Fe _0.2 PO ₄材料的结构，形态和电化学性能的影响。结果表明LiMn _0.8 Fe _0.2 PO ₄以柠檬酸为碳源的材料在0.1、1和5 C时显示164、122和106 mA h g ^-1的高放电容量，在1 C进行100次循环后的容量保持率约为99.6％。归因于较高的表面积，sp ² N–C = N键的强烈峰以及使用柠檬酸作为碳源与冷冻干燥相结合形成的流变相所产生的均匀颗粒分布。流变相辅助固态法是生产性能优异的LiMn _0.8 Fe _0.2 PO ₄材料的有前途的途径。