Rational Design And Application Of Water-based Binders For Silicon Anode

With the increasing demand for electric vehicles in recent years,the role of lithium-ion batteries has attracted more and more attention.Therefore,it is very urgent to develop high-performnace lithium-ion batteries with higher energy density,longer service life,and higher safety.Among a series of new anode materials,silicon has been active in people’s sight with its ultra-high specific capacity and abundant reserve.However,the high expansion rate limits their development.In the entire electrode,although the amount of binder is small,it plays a key role.The traditional commercial PVDF binder cannot limit the expansion of the silicon active material,and is easy to cause fast capacity fading during long cycling.Therefore,the design of new water-system,non-toxic,environmentally friendly binder plays an important role in the development of lithium ion batteries.In this paper,two kinds of water system binder are designed and applied in the silicon anode electrode.The first is the c-PAA-XG binder,which can increase the loading of silicon/carbon to 18.3 mg cm^-2,and can provide an ultra-high reversible areal capacity of 27.7 m Ah cm^-2,which can remain stable for 10 cycles.This binder also has a good compatibility in commercial cathode materials,anode materials,micro/nano materials.The binder achieves high-loading electrodes to meet the needs of high energy density batteries.The second is Alg-DS-80 binder,applied to the silicon anode electrode,which has a capacity retention rate of 95.5%after 100 cycles,thus laying a solid foundation for commercial full battery applications.The two adhesives can not only alleviate the bulk expansion of silicon,but also improve the electrochemical properties.