Developing sustainable energy storage technologies has been attracting significant attentions due to the ever-growing energy needs and depleting fossil fuels. Increasing the energy density of the lithium-ion battery (LIB) is highly required due to their expanding applications from portable electronics to large-scale emerging applications, such as an electric vehicle that requires longer driving distance upon a single charging. Theoretically, using silicon instead of the traditional graphite on anode can raise the capacity up to 10 times higher, while the significant volume change during lithiation and delithiation seriously limits the long cycle life of the silicon anode. In this project, a multiphase graft copolymer of lithium polyacrylate was synthesized and tested as a polymer binder for silicon-based anode in lithium-ion battery. A macro RAFT-CTA was synthesized by amidation reaction of carboxylic acid terminated RAFT-CTA with primary amine on chitosan in aqueous solution, and the following RAFT polymerization of acrylic acid allows the synthesis of well-defined comb-like copolymers, i.e., chitosan-graft-PAA. Further titration of the chitosan-graft-PAA with lithium hydroxide results the comb-like copolymer with chitosan as a backbone with lithium polyacrylate as the side chains. Multi-grafting lithium acrylate with different grafting densities and side chain lengths can be synthesized. The effect of different polymer binders, such as PVDF, PAA, LiPAA and chitosan-graft-PAA and chitosan-graft-LiPAA, on the electrochemical performance is assessed, and galvanostatic test result demonstrated that the comb-like copolymer exhibit the better cycling performance compared with the linear analogue.

Multi-grafting lithium polyacrylate as high-performance polymer binder for lithium-ion battery

253rd National Meeting (2017)

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