稻壳基活性炭对锰酸锂电池倍率性能的影响

稻壳基活性炭(RH-AC)具有天然的多级孔道结构,是由稻壳碳化和活化两步得到的。 用RH-AC和锰酸锂(LMO)混合制备复合电极,以锂片为对电极,组装半电池进行恒流充放电测试。 实验发现:含有质量分数为5%的RH-AC与90.5%的LMO的复合电极(RH-AC5)在5C电流密度循环100圈后比容量为89.3 mA·h/g,容量保持率高于89%,远优于纯锰酸锂电极。 采用循环伏安法计算出的锂离子扩散系数,及利用交流阻抗测试拟合后得到的结果进一步验证了该结论。

Effect of Activated Carbon from Rice Husk on the Rate Performance of Lithium Manganese Oxide Battery

Rice husk activated carbon(RH-AC) was synthesized via facile carbonization and activation basing on previous work. Lithium Manganese Oxide(LMO) and RH-AC were used to prepare composite electrode. Lithium metal was used as the counter electrode. Composite electrode and pure LMO electrode were tested via the galvanostatic charge/discharge(GCD). The results show that the specific capacity of 89.3 mA·h/g at 5 C rate, and the capacity retention of 89% after 100 cycles are obtained for the composite electrode with addition 5% mass fraction of RH-AC(RH-AC5). Obviously, the composite electrode exhibits higher specific capacity with better rate capability and cycle stability than those of LMO electrode. This result was further verified by the impedance simulation result and the lithium ion diffusion coefficients obtained by the cyclic voltammetric method for LMO electrode and RH-AC5 electrode.