Carbon Yarn‐Ball‐Entangled SiO<sub>2</sub> Anode with Excellent Electrochemical Performance for Lithium‐Ion Batteries
Dan Wang, Tongshuai Wang, He Miao, Ting Wang, Hailong Wang
Abstract
Abstract Various nanoscale SiO 2 and their composites have demonstrated superior electrochemical performance as anodes for lithium‐ion batteries. However, both the battery production and real applications require the integration of nanoscale SiO 2 into micrometer‐sized secondary particles while preserving their excellent stability and conductivity, which remains a great challenge. In this work, a unique carbon yarn‐ball structure is successfully synthesized that entangles nanoscale SiO 2 together to build a micrometer‐sized secondary particle. The hook‐like carbon wires closely adhere to individual SiO 2 nanoparticles, which constitute the basic unit of the yarn‐ball structure. The entangled carbon wires create a network of electron conduction highways for SiO 2 , and the yarn‐ball structure provides a resilient 3D matrix that can effectively buffer the anisotropic volume changes of SiO 2 during Li ion insertion/extraction. Under 0.1 A g −1 , the carbon yarn‐ball‐entangled SiO 2 can deliver a 1297 mAh g −1 discharge capacity with a small irreversible capacity of 82 mAh g −1 . The entangled carbon yarn ball firmly maintains its structural integrity during high‐rate cycling (1 A g −1 ), which gives rise to a large accessible capacity (709 mAh g −1 , 90.7% retention for 500 cycles), superior coulombic efficiency (>99.9%), and excellent structural stability.