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

Abstract

AbstractMicrosized‐silicon (µ‐Si, >1 µm) 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, µ‐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 µ‐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 µ‐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 µ‐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.