石墨烯/多孔纳米硅负极的电化学性能

采用酸浸蚀Al-Si合金的方法制备了多孔纳米Si，并用其制作以石墨烯为导电材料的石墨烯/多孔纳米Si负极. SEM和TEM的分析表明两者混合均匀. 作为锂离子电池的负极，该电极在1 mol?L^-1 LiPF₆/EC(碳酸乙烯酯):DMC(碳酸二甲酯) = 1:1(by volume) + 1.5%(by mass)VC(碳酸亚乙烯酯)溶液中、0.5 A?g^-1电流密度下，第120周循环的放电比容量为1842.6 mAh?g^-1，充放电效率为98.6%. 石墨烯的加入不仅提高了电极的导电性，而且减缓了充放电过程中电极多孔纳米结构的衰变.

Electrochemical Properties of Graphene/Porous Nano-Silicon Anode

Porous nano-silicon (Si) was prepared by acid etching Al-Si alloy powder method, and used as an active material for fabricating a grapene/porous nano-Si electrode. The results of SEM and TEM measurements indicated that porous nano-Si powder was uniformly mixed with graphene by emulsification dispersion-ultrasonication method. As an anode for lithium ion battery, the graphene/porous nano-Si electrode presented relatively high performance in 1 mol?L^-1 LiPF6/EC:DMC = 1:1(by volume) + 1.5% (by mass) VC solution. At the charge and discharge current densities of 0.5A?g^-1, the first discharge capacity was 1768.6mAh?g^-1 with coulombic efficiency of 68.3%. The discharge capacity increased in the initial several cycles, and then decayed gradually after 7 cycles. Finally, the discharge capacity was 1842.6mAh?g^-1 with coulombic efficiency of 98.6% after 120th cycles. The excellent cycle property could be attributed to the improvement of electronic conductivity and structural stability of graphene/porous nano-Si material.