Na- and K-Doped Li 2 SiO 3 as an Alternative Solid Electrolyte for Solid-State Lithium Batteries

The search for high-performance solid electrolyte materials with the potential to increase the safety and energy density of next-generation Li-ion batteries is becoming ever more important for the electrification of transport and grid-scale energy storage. In this study, molecular dynamics simulations are used to study ion transport in Na- and K-doped Li 2 SiO 3 as a potential material for future solid-state lithium batteries. Lattice statics calculations are also used to determine the defect energetics of this system, which reveal the ease with which Li 2 SiO 3 can store Na and K. Our calculations reveal low defect formation energies of 0.07 and 1.95 eV for Na and K doping of Li 2 SiO 3, respectively. Room-temperature Li-ion diffusion in Li 2 SiO 3 is significantly enhanced by the inclusion of a low concentration of Na (1 mol %) with a notably low activation energy of 0.34 eV, compared with 0.48 eV for the undoped system. Alternatively, at higher dopant concentrations in excess of 3 mol %, it is K doping that results in an enhancement in Li-ion diffusion rather than Na doping. Our results highlight the potential of doped Li 2 SiO 3 as a solid electrolyte material for Li-ion batteries and encourage further experimental verification of these promising findings.