Study On The Structure Design And Mechanism Of Tin-based Integrated Electrode Materials For Li-ion Batteries

The expansion of the application field of lithium ion batteries puts forward higher requirements on power density and energy density.Due to the low energy density and power density of commercial graphite materials cannot meet the needs of development,there is urgent to develop next-generation anode materials.Tin-based materials have attracted much attention because of its high specific capacity,but the huge volume changes and structural damage during cycling limit its further development.This article focuses on improving the conductivity of tin-based materials and suppressing its volume expansion.A three-dimensional conductive network is designed,and an integrated electrode structure is prepared,which not only improves the whole conductivity of the electrode,but also possess low volume change and stable interface.The integrated electrode exhibits excellent rate property and long cycle stability.This article is mainly focus on the following two parts:?1?Imitate the preparation process of MOF material,grow the SnO₂ material on the surface of the carbon material substrate,and PAN is used as a conductive agent and a binder to construct an integrated electrode.The carbon material substrate,the nitrogen-containing SnO₂ intermediate layer and the coated carbon layer construct a highly efficient conductive network and provide sufficient buffer areas.This design improves the conductivity of the composite material while suppressing the volume change,ensuring the high conductivity and structural stability during cycling,bringing pretty rate performance and long-cycle stability at high current density.?2?The primary grain size is controlled by in situ growth of SnSSe on graphene sheets,and then self-assembled to form a three-dimensional flower-like structure,then an integrated SnSSe/GR@C electrode is prepared by coating and carbonization of polyacrylonitrile.This structure greatly improves the conductivity of the material while reducing the volume expansion in the cycle from 161.8% of pure SnSSe to 38.2%,bringing a stable structure and reaction interface.This structure enhances the transition of electron and lithium ions,so the power density of the material gets improved,delivering a high capacity of 518.4 m A h/g after 850 cycles at 5.0 A/g.