A Universal Binder Enables Stable Operation of High-Capacity Electrodes for Energy-Dense Batteries

Abstract

Developing high-capacity electrode materials with high electrochemical performance is crucial for energy-dense batteries. However, this endeavor faces large challenges, including huge volume variations and unstable interfaces during cycling, resulting in inferior electrochemical performance. Here, a self-healing network with dense hydrogen bonds is reported as a universal binder for stable operation of typical high-capacity electrodes, including silicon-based anodes and sulfur cathodes. The network, created by the reaction between a readily repairable poly(ether-thioureas) and polyacrylic acid, integrates the advantages of self-healing capability and a three-dimensional cross-linked structure. This design imparts fast repairability, outstanding mechanical performance, and large ionic conductivity to the network, which effectively accommodates volume change, stabilizes electrode interface, and enhances reaction kinetics, thereby ensuring the stable operation of various high-capacity electrodes. Thus, the as-constructed silicon anode and sulfur cathode with the self-healing network both achieve outstanding electrochemical performance. For instance, the resulting silicon anodes show a high cycle stability with a capacity of 2447 mAh g⁻¹ after 100 cycles at 1.2 A g⁻¹, and excellent rate capability (1921.8 mAh g⁻¹ at 3 A g⁻¹). This work presents a universal method to ensure the stable operation of high-capacity electrodes for energy-dense batteries through the rational design of binders.