掺杂SiOx负极新材料制备与电化学性能研究

Preparation and electrochemical performance of new doped SiOx anode materials

针对锂离子电池负极材料石墨比容量低的问题,提出一种新型碳线复合纳米二氧化硅(SiO_(2)@CEG)材料的制备。试验通过金属镁盐熔还原SiOx对煅烧条件进行优化,对制备的材料电化学性能进行分析。试验结果表明,在900℃,氩气条件下进行煅烧生成的产物杂质最少。在该条件下制备的SiO_(2)@CEG,伏安扫描曲线几乎完全重合;恒流充放电最初放电容量约为1 192(mA·h)/g,在充电过程中,可释放容量约为1 118(mA·h)/g,不可逆放电容量约为74(mA·h)/g。经过最初几次循环后,SiO_(2)@CEG材料最大放电容量约为709(m A·h)/g,在500次循环中,最大放电容量为643(mA·h)/g,保持率约为90%。在15个循环和20个循环中就快速达到目标库伦效率,在随后的循环过程中,库伦效率保持着近100%。

In order to solve the problem of low specific capacity of graphite as an anode material for lithium-ion batteries,a new carbon wire composite nano-silica(SiO_(2)@CEG)material was proposed.In this experiment,the calcination conditions were optimized by melting and reducing SiOx with magnesium salts,and the electrochemical properties of the prepared materials were analyzed.The test results showed that the impurities in the product produced by calcination at 900℃and argon were the least.The voltammetry scan curves of the SiO_(2)@CEG prepared under these conditions almost completely coincided.The initial discharge capacity of constant current charging and discharging was about 1192(mA·h)/g,and during the charging process,the releasable capacity was about 1118(mA·h)/g,and the irreversible discharge capacity was about 74(mA·h)/g.After the first few cycles,the maximum discharge capacity of the SiO_(2)@CYB material was about 709(mA·h)/g.In 500 cycles,the maximum discharge capacity was 643(mA·h)/g,and the retention rate was about 90%.The target Coulomb efficiency was rapidly achieved in 15 cycles and 20 cycles,and the Coulomb efficiency remained nearly 100%in the subsequent cycles.