锂离子电池用硅基复合负极材料的性能研究

Performance of silicon-based composite as anode materials of lithium-ion batteries

选用比容量较高的氧化亚硅材料配合石墨作为负极,考察氧化亚硅含量对材料电化学性能及其表面成膜和形貌的影响。实验结果表明:增大氧化亚硅含量可有效提高材料的比容量,但其表面较难形成稳定的SEI膜,不可逆损失增大;5%氧化亚硅的LFP/SiO-C软包电池采用较小的充电电流进行循环测试,负极嵌锂过程减缓,可以有效改善SEI膜生成状况,电池经100次循环,膨胀率为102.7%,150次循环时,其容量保持率可达88.27%。

Taking the higher capacity SiO combined with graphite as the anode, the influence of SiO content on the electrochemical properties, SEI forming on the anode surface and its morphology were investigated. The experimental results show that increasing SiO content can effectively improve the specific capacity, but its surface cannot easily form the stable SEI film, and the irreversible loss also increases. LFP/SiO-C pouch cells using 5%SiO were tested. By applying small charging current, the lithium insertion process slows down, and the SEI film formation is improved effectively. After 100 cycles, the expansion rate of pouch cell is 102.7%;after 150 cycles, the capacity retention rate is 88.27%.