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

Abstract

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 Li3InCl6 and anti-perovskite-type Li2OHCl, show good thermal stability with oxides LiCoO2, LiMn2O4, and Li4Ti5O12 up to 320 °C. Moreover, anti-perovskite-type Li2OHCl shows a chemical reactivity with other battery materials (eg., LiFePO4, LiNi0.8Co0.1Mn0.1O2, Si-C, and Li1.3Al0.3Ti1.7(PO4)3) at 320°C, which reaches the melting point of Li2OHCl. It indicated that Li2OHCl has relatively high chemical reactivity after melting. In contrast, rock-salt-type Li3InCl6 shows higher stability and interfacial compatibility. This work delivers insights into the selection of suitable battery materials with good compatibility for ASSLBs.

Interplay of Cathode–Halide Solid Electrolyte in Enhancing Thermal Stability of Charged Cathode Material in All-Solid-State Batteries

“…This evolution may originate from the intrinsic fragility of In−Cl bonding that can be readily broken by elements possessing high electronegativity, such as oxygen or hydroxide ions. 40 Above 350 °C, InOCl underwent further decomposition, vanishing at 400 °C and leading to the emergence of In 2 O 3 (green cross). The increase in the Cl 2 gas signals above 350 °C in the EI-MS spectra (Figure 2d) can be attributed to the release of Cl from the breakdown of InOCl and the phase transition to In 2 O 3 .…”

“…In addition, the NCM/LIC composite shows LiCl (red triangle) and InOCl (orange diamond) evolution from 300 °C due to the interaction between NCM and LIC. This evolution may originate from the intrinsic fragility of In–Cl bonding that can be readily broken by elements possessing high electronegativity, such as oxygen or hydroxide ions . Above 350 °C, InOCl underwent further decomposition, vanishing at 400 °C and leading to the emergence of In 2 O 3 (green cross).…”