Graphene Based As The Conductive Additives Of Lithium-ion Batteries

The conductivity of the positive and negative materials of lithium ion batteries is not ideal,which will affect the performance of the battery.It is necessary to add a conductive agent to improve the conductivity.At low rate,the graphene conductive agent and the active material are "point-to-face contacting",which makes the contact efficiency higher,resulting in excellent battery performance.At high rate,graphene as a planar conductive agent will hinder the movement of lithium ions,causing serious polarization of the battery,further affecting battery performance.This topic is the synthesis of a small size graphene(sGN).By controlling the size ratio of active material to graphene,the influence of lithium ion motion caused by the planar structure of graphene is avoided.Thus,the system can improve the rate performance of the battery and is suitable for the use of power lithium ion batteries.The details are as follows:1.Different sizes of graphene were synthesized and the effects of process conditions on the synthesis of graphene were investigated.I found that the amount of KMnO4 added must ensure that the graphite is completely oxidized.When the intermediate temperature reaction time is 2 h,the quality of the prepared graphene is good.2.Explore the impact of commercial conductive agents on all aspects of battery performance.20 wt%of KB,super-p,and 10 wt%commercial graphene have the largest discharge specific capacity and the most cycles.3.Explore the effects of synthetic sGN on all aspects of battery performance.The 10 wt%sGN discharge has the largest specific capacity,the most cycles,the best rate performance,and the smallest internal resistance and charge transfer internal resistance.4.I studied the performance effects of binary conductive agents(sGN with KB)on all aspects of lithium-ion batteries.6 wt%sGN and 6 wt%KB were combined as a binary conductive agent.The battery assembled by the binary conductive agent has better cycle performance.4 wt%sGN and 12 wt%KB were combined as a binary conductive agent.A battery assembled using a binary conductive agent has the best rate performance.