《Mitigation of the instability of ultrafast Li-ion conductor Li6.6Si0.6Sb0.4S5I enables high-performances all-solid-state batteries》
Solid-state batteries with excellent safety and high energy density display great potential as next-generation energy storage devices. However, few solid electrolytes can fulfill the high ionic conductivity and good chemical/electrochemical stability at the same time. Herein, pure argyrodite Li6.6Si0.6Sb0.4S5I electrolyte with high Li-ion conductivity (9.0 mS cm-1) and poor stability is successfully synthesized via the typical mechanochemical route. Interfacial instability of this electrolyte with different electrode materials is investigated. A highly conductive Li3InCl6 electrolyte with a wide voltage window and excellent chemical/electrochemical stability with active material and carbon conductive are introduced in the battery configuration, resulting in superior electrochemical performances with the bare LiNi0.7Mn0.2Co0.1O2 cathode. The corresponding battery delivers a discharge capacity of 162.1 mAh g-1 at 0.5C and maintains 83.8% of the capacity after 200 cycles at room temperature. Moreover, this battery with a cathode mass loading of 6.37 mg cm-2 displays discharge capacities of 197.5 mAh g-1 and 73.4 mAh g-1 at the beginning when cycled at 0.5C and 0.1C under the operating temperature of 60 oC and -20 oC, respectively. Superior stable cycling performances are also achieved for the battery at both temperatures. Due to the fast ionic conductivity from Li6.6Si0.6Sb0.4S5I and high electronic conductivity from carbon in the cathode, the thick electrode configurations with huge mass loadings of 50.96 mg cm-2 and 76.43 mg cm-2 also exhibits good capacities and highly reversible cyclability. This work provides a guideline for enabling superior conducting sulfide electrolytes with poor stability in thick electrode configuration solid-state batteries.
http://https://www.chinesechemsoc.org/doi/10.31635/renewables.023.202200021
