Modified polyacrylonitrile cross-linked with carboxymethyl cellulose constructing a hydrogen bonding network for high-performance silicon anodes

Abstract

Polyacrylonitrile (PAN) has been investigated as an effective binder and coating material for silicon anodes in lithium ion batteries due to its inherent elasticity and the propensity to form conjugated structures. However, achieving a balance among the conductivity, binding strength and elasticity is a challenge faced by researchers. Herein, the structural and property evolution of PAN during calcination is systematically investigated to realize balanced conductivity and elasticity. Additionally, a hydrogen bonding network is established to address the issue of low binding strength by applying carboxymethyl cellulose (CMC) as the thickening agent for PAN. The as-prepared Si@cPAN@CMC electrode demonstrated a discharge capacity of 2358 mA h g⁻¹ after 100 cycles at 1 A g⁻¹, with an initial coulombic efficiency (ICE) of 91.0% and a capacity retention of 93.8%. Furthermore, the electrode exhibited a stable cycling life of nearly 700 cycles under a limited charge and discharge capacity of 1000 mA h g⁻¹ at 1 A g⁻¹, and the electrode with a mass loading of 3.0 mg cm⁻² demonstrated a high areal capacity of 5.0 mA h cm⁻² after 50 cycles at 0.5 A g⁻¹. Therefore, this work opens a new avenue for designing a multifunctional coating layer for promising anodes of lithium-ion batteries.