Temperature-dependent compatibility study on halide solid-state electrolytes in solid-state batteries

All-solid-state lithium batteries (ASSLBs) have attracted much attention owing to their high safety and energy density compared to conventional organic electrolytes. However, the interfaces between solid-state electrolytes and electrodes retain some knotty problems regarding compatibility. Among the various SSEs investigated in recent years, halide SSEs exhibit relatively good interfacial compatibility. The temperature-dependent interfacial compatibility of halide SSEs in solid-state batteries is investigated by thermal analysis using simultaneous thermogravimetry and differential scanning calorimetry (TG–DSC) and X-ray diffraction (XRD). Halide SSEs, including rock-salt-type Li(3)InCl(6) and anti-perovskite-type Li(2)OHCl, show good thermal stability with oxides LiCoO(2), LiMn(2)O(4), and Li(4)Ti(5)O(12) up to 320 °C. Moreover, anti-perovskite-type Li(2)OHCl shows a chemical reactivity with other battery materials (eg., LiFePO(4), LiNi(0.8)Co(0.1)Mn(0.1)O(2), Si-C, and Li(1.3)Al(0.3)Ti(1.7)(PO(4))(3)) at 320°C, which reaches the melting point of Li(2)OHCl. It indicated that Li(2)OHCl has relatively high chemical reactivity after melting. In contrast, rock-salt-type Li(3)InCl(6) shows higher stability and interfacial compatibility. This work delivers insights into the selection of suitable battery materials with good compatibility for ASSLBs.