Volumetric Stress Managements on Silicon Anode of Lithium‐Ion Batteries by a Self‐Adaptable Binder
Shuai Wu, Lanying He, Lu Yue, Jingang Zheng, Lixiang Li, Xin Geng, Chengguo Sun, Hongwei Zhao, Guangshen Jiang, Di Fang, Baigang An
Abstract
The intrinsic volume changes (about 300%) of Si anode during the lithiation/delithiation leads to the serious degradation of battery performance despite of theoretical capacity of 3579 mAh g −1 of Si. Herein, a three‐dimensional (3D) conductive polymer binder with adjustable crosslinking density has been designed by employing citric acid (CA) as a crosslinker between the carboxymethyl cellulose (CMC) and the poly(3,4‐ethylenedioxythiophene) poly‐(styrene‐4‐sulfonate) (PEDOT:PSS) to stabilize Si anode. By adjusting the crosslinking density, the binder can achieve a balance between rigidity and flexibility to adapt the volume expansion upon lithiation and reversible volume recovery after delithiation of Si. Therefore, Si/CMC‐CA‐PEDOT:PSS (Si/CCP) electrode demonstrates an excellent performance with high capacities of 2792.3 mAh g −1 at 0.5 A g −1 and a high area capacity above 2.6 mAh cm −2 under Si loading of 1.38 mg cm −2 . The full cell Si/CCP paired with Li(Ni 0.8 Co 0.1 Mn 0.1 )O 2 cathode discharges a capacity of 199.0 mAh g −1 with 84.3% ICE at 0.1 C and the capacity retention of 95.6% after 100 cycles. This work validates the effectiveness of 3D polymer binder and provides new insights to boost the performance of Si anode.