Carbon-Binder Design for Robust Electrode-Electrolyte Interfaces to Enable High-Performance Microsized-Silicon Anode for Batteries

Microsized-silicon (& mu;-Si, >1 & mu;m) is one of the ideal anodes for lithium-ion batteries due to its low-cost, high tap density, and high specific capacity. However, during repeated lithiation/delithiation processes, & mu;-Si undergoes huge volume changes. This leads to continued capacity loss during cycling due to severe particle pulverization, separation from the conductive network and uncontrolled growth of an unstable solid-electrolyte interphase (SEI). Herein, an electrode construction strategy is proposed by carbonization of the slurry-casting & mu;-Si electrode. The organic binder serves as both carbon resource and physical framework, which is carbonized to form a carbon binder that is chemically bonded with the & mu;-Si particles and within the electrode. The electrode with carbon binder ensures stable electric channel and promotes formation of a stable and passivating SEI at the interface with a high & mu;-Si content up to 82 wt%. The carbon binder offers physical buffer that shield against localized strain and modifies the surface reactivity, which enables a high initial Coulombic efficiency (91.85%) and stable cycle performance at commercial-level areal capacities (2 mAh cm(-2)). This work offers an easily scalable yet practical approach for the current battery industry without any electrolyte modification or complicated manufacturing methods.