纳米银复合的多孔生物质硅材料的制备及储锂性能

Reversible Storage of Lithium in Porous Biomass Silicon Decorated Silver Nanoparticles

以废弃的谷壳为原料,通过镁热还原-银镜反应法成功制备了多孔硅/银复合纳米材料,并研究其结构形貌及储锂性能。结果表明:采用谷壳为原料获得的硅/银复合材料为纳米多孔结构,其粒径约为10~20 nm,纳米银的原位复合可显著提高电极的循环稳定性能、倍率性能和比容量。原位纳米银粒子复合后的Si/Ag电极50次循环后的容量依然能维持750.4 mA·h/g,为石墨类碳材料容量的2倍以上,较生物质硅电极提高了370.2 mA·h/g,采用800 mA/g的电流密度进行大电流充放电时,Si/Ag电极表现出618.3 mA·h/g的可逆容量,远高于Si电极380.2 mA·h/g的容量。性能的改善缘于复合后本体材料较高的导电性和电极/电解液界面的优良性能。

A porous Si/Ag composite material derived by waste rice husk was synthesized via magnesiothermic reduction-silver mirror reaction.The structure,surface morphology and lithium storage performance were investigated.The results show that the particle sizes of obtained biomass silicon material with a porous structure are 10-20 nm,and the cycle performance,rate performance and specific capacity of the electrode all are improved by recombining silver nanoparticles.The capacity of electrode with the silver particles can retain 750.4 m A·h/g after 50 cycles,which is twice greater than that of graphite,and it is 370.2 mA·h/g greater than that of pure biomass silicon electrode.The biomass Si/Ag electrode exhibits the specific capacity of 618.3 m A·h/g at current density of 800 mA/g,which is higher than that of biomass silicon(380.2 m A·h/g),due to the higher conductivity of Si/Ag nanomaterial and excellent property of electrode/electrolyte interface.