Crosslinked Polymer Binder via Phthalic Acid for Stabilizing SiOx Anodes

Abstract

AbstractIt is widely recognized that SiOx is a feasible anode material for the next generation lithium‐ion batteries because of its high capacity, low cost, environmental friendliness, and abundant available storage. However, the enormous volume expansion and irreversible by‐products during lithiation can result in the rapid capacity degradation and low coulombic efficiency. The commercial binders of carboxymethyl cellulose (CMC) and polyvinylidene difluoride cannot afford the volume change. Herein, a rational crosslinked binder is synthesized through an in situ condensation reaction between CMC and phthalic acid (PA). With rich hydroxyl groups bonded to the homogeneous SiO2 nanodomain, the enormous volume expansion of the SiOx anode can be restricted efficaciously. Therefore, the SiOx@CMC‐PA electrode delivers a reversible specific capacity of 671 mAh g−1 at 500 mA g−1 after 200 cycles and a high average coulombic efficiency of 99.2%, much higher than 226.3 mAh g−1 of SiOx@CMC electrode. It demonstrates that this work offers a cost effective and available strategy to achieve high performance binder for Si‐based anode materials.