High Long‐Term Performance of 325‐Mesh Silicon Microparticle Anodes in Li‐Ion Batteries Enabled by Hierarchical Structure of Graphene Oxide and DNA Binder

Abstract

AbstractThe promise of silicon anodes for lithium‐ion batteries (LIBs), owing to the high theoretical capacity, is significantly affected by the huge volume changes (over 300%) during the lithiation/delithiation process. This leads to particle cracking during cycling impacting the electrode at multiple levels, from continued solid‐electrolyte interphase formation, particle contact losses, to delamination of the coating from the current collector. As a results, there is increased electrolyte consumption, and significantly shortened cycle life, hindering its commercial application. The problem is severe for commercially viable larger silicon microparticles (SiMPs > 1 µm). Herein, the cycling of 325 mesh (≤45 µm) SiMPs is successfully demonstrated using a composite binder consisting of inner graphene oxide coating and outside DNA polymer. The resultant hierarchical structure, with cycling‐induced 3D interconnection, maintains the electrodes integrity, as well as helps to stabilize the SEI. Thus, an excellent cycle life is observed, retaining a capacity of 808 mAh·g−1 after 450 cycles at a current density of 840 mA·g−1. This double protection strategy with a robust particle coating and a chemically bonded soft polymer offers an effective strategy for cyclability of SiMPs in practical LIBs.