化成制度对富锂锰基/硅碳体系电池产气及电化学性能影响

Influence of formation process on gas generation and electrochemical performance of Li-rich/Si@C Li-ion batteries

针对富锂锰基正极材料独特的首周充电特性,设计了一种脉冲化成制度,通过优化化成制度减少富锂锰基/硅碳体系电池化成过程中的产气量,提高电池的循环电化学性能。通过GC-MS,SEM,XPS和电化学测试表明,对比传统的化成制度,采用脉冲化成制度后电池的产气量降低了37%左右。此外,脉冲化成制度能在正、负极活性物质表面形成一层致密的膜结构,同时可以缓解化成过程中电芯结构的应力,稳定电极结构。脉冲化成制度还可以有效地节省化成时间,将时间从102.6 h缩短至81.5 h。提升了长循环过程中的电化学稳定性,500周次循环后,容量保持率和中值电压均得到了显著的提升。

According to the unique characteristics of Li-rich manganese-based cathode materials during the first cycle charge,a pulse formation process was designed to reduce the gas production during the formation process and improve the electrochemical performance of the Li-rich/Si@C batteries.The GC-MS,SEM,XPS and electrochemical test results show that,compared with the traditional formation process by optimizing the formation process,the gas production of the batteries under the pulse formation is reduced by about 37%.After pulse formation,a dense film structure can be formed on the surface of the positive and negative active materials,the stress of the cells during the formation process can be relieved.The pulse formation process can also effectively save the formation time,shorten the time from 102.6 h to 81.5 h.In addition,the electrochemical stability during cycle is improved,after 500 cycles,both the capacity retention rate and the median voltage have been significantly improved.