Low-temperature rate charging performance of all-solid-state batteries under the influence of interfacial contact loss

In solid-state lithium-ion batteries (SSBs), the non-wetting characteristics of solid electrolytes (SE) shift the interface from the conventional solid-liquid to a solid-solid, which increases contact resistance and accelerates capacity decay. Additionally, low temperatures adversely affect SSBs performance. This paper delves into the electrochemical behavior of SSBs under low-temperature conditions and conducts an in-depth analysis of the influence of solid-solid interface contact loss on charging rate performance. The results show that both the loss of interfacial contact and the increase of charging rate contribute to capacity degradation of SSBs at low temperatures. Appropriate external pressure can mitigate contact loss as it progressively tightens the interface. However, further pressure increases become pointless after full contact is achieved. Notably, as the temperature decreases and the current rate increases, the bottleneck limiting battery capacity shifts from the cathode/SE interface to the anode/SE interface. In addition, due to the different Young's moduli of the anode and cathode, the critical external pressure for enhancing battery performance has been changed from 60 MPa to 13.5 MPa. This study provides an in-depth exploration of the intrinsic mechanism of SSBs in low-temperature environments and proposes performance improvement pathways, contributing to the development and application of SSBs in low-temperature scenarios.