Overcoming Chemo-Mechanical Instability at Silicon-Solid Electrolyte Interfaces in Solid-State Batteries
Lammi Terefe Kitaba, Yosef Nikodimos, Semaw Kebede Merso, Bereket Woldegbreal Taklu, Gashahun Gobena Serbessa, Woldesenbet Bafe Dilebo, Tsung‐I Yeh, Joshua Alexander Iskandar, Fernando Fortes de Valência, Chia‐Yu Chang, Chia Lung Hsieh, Shawn D. Lin, She‐Huang Wu, Wei‐Nien Su, Bing‐Joe Hwang
Abstract
High Resolution Image Download MS PowerPoint Slide Silicon is the preferred choice for lithium-ion battery anodes due to its high theoretical capacity and low lithiation potential. However, achieving high areal capacity with silicon anodes in solid-state batteries (SSBs) is challenging because of poor electronic and ionic conductivity, as well as chemo-mechanical instability at the silicon|solid electrolyte (Si|SE) interfaces. Here, we propose fabricating and testing composite anodes made of nanosized Si powder embedded in partially fluorinated graphene (Si-FG) and Li 6 PS 5 Cl (LPSCl) sulfide SE. X-ray photoelectron spectroscopy revealed that the in situ formation of LiF-rich SEI can protect against SE decomposition at the interface in the Si-FG-LPSCl composite anode. FIB-SEM and EIS analyses also indicate a stable structure and low interfacial resistance after one cycle for a composite anode containing FG. The incorporation of partially FG enhances both electronic (through heterojunction formation with Si) and ionic conductivities, buffers significant volume changes, and ensures chemo-mechanical stability in the composite anode. The Si-FG-LPSCl composite anode in SSBs delivered high discharge/charge capacities of 3499/2994 mAh g –1 at a C-rate of C/20 and an ICE of 85.6% in a half cell. This work provides valuable insights for advancing high-capacity Si composite anodes to meet future energy needs.