石墨烯改性硅基负极材料的研究进展

Research Progress of Graphene Modified Silicon-based Anode Materials

随着电动汽车的快速发展,对锂离子电池的负极材料有了越来越高的要求。目前商用锂离子电池的负极材料还是以石墨为主,但是石墨负极的理论比容量较低(为372 mAh/g),严重限制了锂离子电池的能量密度。硅的理论比容量高达4200 mAh/g,被认为是最有前途的锂离子电池负极材料之一。然而,硅负极材料在锂化的过程中会伴随着巨大的体积膨胀效应,导致电极材料破裂和粉碎,从而大幅度降低电池的循环稳定性,并且硅的电导率不理想,也限制了其倍率性能和循环性能。用石墨烯对硅负极材料进行改性,有望缓解其电极材料的体积膨胀以及导电性差的难题。本文重点阐述了石墨烯对于硅基负极材料的性能提升机理,期望对未来石墨烯改性硅基负极材料的制备和研究提供思路。

With the rapid development of electric vehicles,there are urgent requirements for high performance anode materials of lithium-ion battery.Currently,the negative electrode material for commercial lithium-ion batteries is mainly graphite.However,the theoretical specific capacity of graphite anode is low(372 mAh/g),which seriously limits the energy density of lithium-ion battery.The theoretical specific capacity of silicon is up to 4200 mAh/g,which is considered as one of the most promising anode materials for lithium-ion battery.However,the silicon anode material will be accompanied by a huge volume expansion effect in the lithiation process,resulting in the fracture and comminution of the electrode material,which greatly reduces the cycle stability of the battery.In addition,the conductivity of silicon is not ideal,which also limits its rate performance and cycle performance.The modification of silicon with graphene is expected to alleviate the problems of volume expansion and poor conductivity of electrode materials.In this paper,we focus on the mechanism of graphene improving the performance of silicon-based anode materials.It is expected to provide ideas for the preparation and research of graphene modified silicon-based anode materials in the future.