Rational design of trifunctional conductive binder for high-performance Si anodes in lithium-ion batteries

Silicon (Si) has been regarded as a candidate for high-energy-density lithium-ion batteries (LIBs) because of its excellent specific capacity. Binders, as an essential component in Si anodes, play a key role in enhancing the electrochemical performance of LIBs. In this study, a multifunctional binder named LP19 simultaneously possessing high electron conductivity, high Li-ion conductivity as well as ameliorative mechanical performances was synthesized by assembling the lithiated PAA (LiPAA) and highly conductive PEDOT:PSS molecules. The lithiation treatment of PAA is conducive to the transport of lithium ions, while the double conductive network constructed by conductive PEDOT:PSS and Super P guarantees the stable electric connectivity during lithiation and delithiation processes. Moreover, the optimization of the internal configuration of the molecules realizes the structural and cycling stability of the Si anode. As a consequence, the Si anode utilizing this binary and multifunctional conductive binder demonstrated pronounced cycling stability (2165 mAh g−1 after 200 cycles) and rate performance (1750 mAh g−1 at 8.0 A g−1). This work provided a novel design strategy of polymeric binders to promote progress toward high-performance LIBs.