A garnet-electrolyte based molten Li-I₂ battery with high performance

Lithium-iodine (Li-I₂) battery exhibits high potential to match with high-rate property and large energy density. However, problems of the system, such as evident sublimation of iodine elements, dissolution of iodine species in electrolyte, and lithium anode corrosion, prevent the practical use of rechargeable Li-I₂ batteries. In this work, a molten Li-I₂ typical cell design which has distinct advantages based on the solid-state garnet electrolyte with the eutectic iodate cathode is firstly developed. The U-shaped ceramic electrolyte tube can separate Li anode from the eutectic iodate cathode, so as to better tackle the above-mentioned inherent challenges for the liquid electrolyte systems. Without self-discharging and lithium anode corrosion, this solid-state battery system demonstrates high safety margin and excellent electrochemical performance. Also, the simple battery structure also indicates the easy assembly process and recycling of electrode materials. With the cathode loading of 593 mg in a single cell, an energy density of ~ 506.7 Wh·kg⁻¹ was achieved at 1 C and a long-term cycling life for 2,000 cycles also displays negligible capacity decay.