Interface Design of Solid–Liquid Hybrid Electrodes for High‐Energy‐Density Flexible Lithium‐Ion Batteries
Wenyan Chen, Zhen Zhang, Fangchang Zhang, Zhenyao Wei, Pengxian Li, Chao‐Yang Wang, Meng Gu, Yonghong Deng, Jian Chang
Abstract
Abstract The silicon microparticles (SiMPs) offer a promising solution for high‐energy‐density lithium‐ion battery systems. However, the inevitable volume expansion (>300%) of SiMPs during alloying often leads to particle breakage, interface rupture, and electrode separation, resulting in rapid capacity decay. Herein, an effective strategy is proposed for designing a novel solid–liquid hybrid electrode (Si@EGaSn) for high‐energy‐density flexible lithium‐ion batteries. The Si@EGaSn electrode has a liquid‐phase top layer containing SiMPs and a solid‐phase copper gallium alloy bottom layer. The top layer can not only electrically connect the fractured SiMPs, but also form a stable solid electrolyte interface during alloying processes. The bottom layer can firmly adhere the electrodes to the current collector. Consequently, the optimal Si@EGaSn electrode delivers a highly reversible capacity of 767.1 mAh g −1 at 0.5 A g −1 and a high capacity retention of >99% during 200 cycles. After loading the electrode into metallic textiles, the assembled high‐voltage pouch cell of NCM811//Si@EGaSn shows a high areal capacity of 3.2 mAh cm −2 , high volumetric energy density of 500 Wh L −1 and negligible capacity decay during 3000 flexing cycles at a small bending radius of 4.0 mm. This work provides a new electrode design approach to achieve high‐energy‐density flexible lithium‐ion batteries.