A\nHigh-Performance Polyurethane–Polydopamine\nPolymeric Binder for Silicon Microparticle Anodes in Lithium-Ion Batteries

Abstract

Micro\nsilicon (Si) has been one of the most promising anode materials\nfor lithium-ion batteries (LIBs) due to high theoretical specific\ncapacity and material sources. Nonetheless, an unavoidable huge volume\nexpansion of Si microparticles (SiMPs) and the uncontrolled growth\nof the solid–electrolyte interphase (SEI) during the cycling\nstill inhibit its commercialization. Among the strategies to overcome\nthese problems, the design of a polymer binder is more feasible. Herein,\na binder derived from two of the most common polymers, polyurethane\n(PU) and polydopamine (PDA), has been synthesized by a simple heating\nand mixing method for SiMP anodes in LIBs. In the PU–PDA binder,\nthe synergistic effect of PU and PDA enables it to adapt to the volume\nexpansion of SiMPs and maintain the electrode integrity and provides\nexcellent cycling performance and long cycle life. The SiMP anodes\nwith the PU–PDA binder have a capacity retention above 1000\nmA h g^–1 after 1000 cycles at a current density\nof 0.2 C and could deliver a discharging specific capacity of 1399\nmA h g^–1 at 4 C. Our research provides a safe, simple,\nand efficient PU–PDA polymer binder for SiMP anodes in the\nnext-generation LIBs.