Room-Temperature Solid-State Lithium-Ion Battery Using a LiBH4-MgO Composite Electrolyte

LiBH4 has been widely studied as a solid-state electrolyte in Li-ion batteries working at 120 degrees C due to the low ionic conductivity at room temperature. In this work, by mixing with MgO, the Li-ion conductivity of LiBH4 has been improved. The optimum composition of the mixture is 53 v/v % of MgO, showing a Li-ion conductivity of 2.86 x 10(-4) S cm(-1) at 20 degrees C. The formation of the composite does not affect the electrochemical stability window, which is similar to that of pure LiBH4 (about 2.2 V vs Li+/Li). The mixture has been incorporated as the electrolyte in a TiS2/Li all-solid-state Li-ion battery. A test at room temperature showed that only five cycles already resulted in cell failure. On the other hand, it was possible to form a stable solid electrolyte interphase by applying several charge/discharge cycles at 60 degrees C. Afterward, the battery worked at room temperature for up to 30 cycles with a capacity retention of about 80%.

Automated summary

Research has shown that by mixing with MgO, the Li-ion conductivity of LiBH4 can be improved, but there are still lifecycle issues at room temperature, which can be mitigated by applying multiple charge/discharge cycles at 60 degrees C to form a stable solid electrolyte interphase.