Tough Composite Networks Combining High Ionic and Electronic Conductivity for Stabilizing Silicon Microparticles Anodes

Microsized silicon (μSi) anodes take advantage of low-cost, high tap density, and high theoretical capacity (∼4200 mAh g–1). However, poor cycle stability is presented because of huge volume change during cycling, which seriously limits their practical application in commercial lithium-ion batteries. Herein, a tough composite network combining high electronic and ionic conductivity is developed to stabilize the operation of the μSi anode. The resultant μSi electrode exhibits a high capacity of 3789.0 mAh g–1 with a high initial Coulombic efficiency (ICE) of 92.2% at 100 mA g–1, high-rate capability (1636.0 mAh g–1 at 3 A g–1), and good cycle stability with a high capacity retention of 92.0% from 1908.7 mAh g–1 at 15th to 1755.9 mAh g–1 at 135th cycle under 2 A g–1. The excellent electrochemical performance is attributed to the high stretchability (560%) of the 3D structure of the composite network, which can preserve the integral electrode structure, providing rapid electronic conductivity and ionic conductivity during cycling and resulting in outstanding electrochemical performance. This work offers a facile strategy for the development of a tough network combining high electronic and ionic conductivity to enhance the electrochemical performance of high-capacity Si anodes and beyond for energy-dense batteries.