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Using conductive binders, instead of the traditional binders and conductive additives, is an effective way to increase the specific capacity and long cycle life of the silicon (Si) anode. However, the rigid conductive binders of Si anodes tend to form cracks during the repetitive huge volume changes of Si. Here, a novel n-type conductive binder, multi-block polymer of poly(1-pyrenemethyl methacrylate) and polybutadiene (PPy- b -PB) was designed. The polybutadiene (PB) rubber was incorporated into the conductive binder by combining condensation and reversible addition-fragmentation chain transfer polymerization. With high initial coulombic efficiency of 77.9%, the PPy- b -PB/Si anode possesses high reversible capacity (2274 mAh g−1) and capacity retention (87.1%) at the rate of 0.2 C (0.84 A g−1) after 200 cycles. The superior cyclic performance of the PPy- b -PB can be ascribed to the PB rubber, which enhanced the reversible deformation ability, flexibility, and adhesion length scale of the binder, without with a negligible change of the charge-transfer resistance for the anode. The original structure and the preparation method of the multi-block conductive binder provide a new way to manufacture multifunctional binders. A n-type multi-block polymer PPy- b -PB of poly(1-pyrenemethyl methacrylate) (PPy) and polybutadiene (PB) was designed to enhance the reversible deformation ability, flexibility, and adhesion length scale of the conductive binder PPy. With high initial coulombic efficiency of 77.9%, the PPy- b -PB/Si anode possesses high reversible capacity (2274 mAh g−1) and capacity retention (87.1%) at the rate of 0.2 C (0.84 A g−1) after 200 cycles. Image 1 • A novel multi-block binder was prepared by Condensation and RAFT polymerization. • The binder was used as conductive binder for Si anodes in Li-ion batteries. • Reversible deformation ability of the binder was improved with polybutadiene. • High capacity and cycling stability of Si anode was achieved by using the binder. [ABSTRACT FROM AUTHOR]

Abstract Silicon is one of the most promising anode materials for the next-generation high energy density lithium-ion batteries as its superior specific capacity and ultralow lithiation/delithiation voltage. Whereas, silicon suffers massive volume change during cycling, resulting in drastic pulverization of active material and iterative growth of solid electrolyte interphase, largely limiting their widely applications. To address the challenge, water-soluble glycinamide modified PAA (PAA-GA) is synthesized through a facile and low-cost coupling method as a polymer binder to assemble silicon anode for alleviating its huge volume change. The carboxyl and double amide groups of the PAA-GA can form hydrogen bonds with the hydration layer of silicon, and meanwhile the double amide groups of PAA-GA can form double hydrogen bonds via interchain cohesion. These strong supramolecular interactions are reversible and can recover the dissociated bonds more efficiently upon the elimination of the mechanical stress. The PAA-GA-based silicon electrodes exhibit excellent cycling stability and high coulombic efficiency, demonstrating the PAA-GA binder being great potential in fabricating high energy density silicon anodes for next-generation lithium-ion batteries. Graphical abstract Image 1 Highlights • Glycinamide-based binder was synthesized via a facile coupling method. • Water-soluble binders were used for silicon anodes in lithium ion batteries. • A high capacity and good cyclestability were achieved by using the modified binder. [ABSTRACT FROM AUTHOR]