LiMn_(0.75)Fe_(0.25)PO_(4)基混合正极材料性能调控研究

Performance study of LiMn_(0.75)Fe_(0.25)PO_(4)-based mixed cathode materials

重安全、降成本是未来锂电池发展的趋势。为了兼顾磷酸锰铁锂的高安全性能和三元正极材料的高比容量,采用物理混合法将磷酸锰铁锂(LMFP)与三元正极材料(NCM)进行混合,探究了不同混合量和充放电区间对混合正极材料电化学性能的影响。优化结果表明,掺入NCM后,电压跳水现象得到抑制,掺杂量为30%时,在25℃室温、2.0~4.4 V、1 C条件下循环200次,剩余比容量131.8mAh/g,容量保持率为96.3%。同时,穿刺实验中看不到明显的火花现象。

Safety-oriented and cost-reducing are the future development trend of lithium battery.In order to take into account the high safety of lithium manganese iron phosphate(LMFP)and the high specific capacity of the ternary cathode material(NCM),the physical mixing method was used to mix such two active materials into mixed cathode materials,and testify the effect of different mixing amounts and charge discharge intervals on the electrochemical performance of mixed cathode materials.The optimized results showed that the voltage diving phenomenon was suppressed after the addition of NCM.When the mixed amount was 30%of NCM,the remaining 131.8 mAh/g was left after 200 cycles under the conditions of 25℃room temperature,2.0~4.4 V and 1 C,and the capacity retention rate was 96.3%.There was no obvious spark phenomenon in the puncture test.