锂离子电池用纳米Sn/SnSb合金三维复合负极的制备及性能

采用多步电沉积法制备的三维多孔铜箔作为集流体、低温液相化学还原法制备的纳米Sn/SnSb 合金作为负极材料, 制备出一种新型三维多孔结构的纳米Sn/SnSb合金复合负极. 通过与普通负极电化学性能的对比实验发现, 这种新型三维复合负极具有如下优点: 三维多孔网络结构提高了负极活性材料与集流体之间的结合力, 使不含粘结剂电极的制备成为可能; 有效缓解了高容量负极活性材料在充放电过程中的体积膨胀, 提高了负极活性材料的循环性能, 当循环到第30周时, 普通负极剩余容量为初始容量的33%, 而三维复合负极剩余容量为初始容量的41%; 三维铜箔集流体的特殊结构为高容量负极活性材料提供了一个良好的导电环境, 使电极反应进行得更加完全, 从而获得了更高的电极比容量, 普通负极初始容量为480 mAh·g-1, 而三维复合负极达到了800 mAh·g-1. 纳米Sn/SnSb合金三维复合负极良好的电化学性能为锂离子电池负极结构的设计开发提供了新的思路.

Preparation and Performance of a Three-dimensional Nano-Sn/SnSb Composite Anode for Lithium Ion Batteries

A novel three-dimensional composite anode was prepared by using three-dimensional copper foil with micro-holes for collector and nano-Sn/SnSb alloys powders for active materials. The nano-Sn/SnSb alloys were synthesized by liquid chemical reduction methods at low temperature and the collector was obtained via multiple-step electrodeposition. Advantages of the new three-dimensional composite anode were investigated by comparing its electrochemical performance with that of normal planar anode: three-dimensional structure of the electrode enhanced the combination between active materials and the collector, which increased the possibility for the preparation of anode without binder; the novel anode effectively buffered the volume expansion of high capability active materials during charge/discharge cycles and therefore increased the capacity retention of the electrode. Compared to 33%of the initial charge capacity of normal anode after 30 cycles, the capacity retention of three-dimensional composite anode was 41% of the initial charge capacity; special structure provided a well environment for transferring charge, which made the process of the reaction more complete and therefore higher capacity. The initial specific charge capacity of normal anode was 480 mAh·g-1 and that of three-dimensional composite anode achieved 800 mAh·g-1. The advantages and attractive electrochemical performance of the three-dimensional nano-Sn/SnSb composite anode provide a new thought for structure design and development of anode for lithiumion battery.