Structural and electrochemical properties of Fe- and Al-doped Li3V2(PO4)3 for all-solid-state symmetric lithium ion batteries prepared by spray-drying-assisted carbothermal method

• Fe- and Al-doped Li3V1.9M0.1(PO4)3 single phase materials were prepared by spray-dry assisted carbothermal reaction.
• Fe and Al doping increase electric conductivity and enhance the reversible capacity of Li3V1.9M0.1(PO4)3.
• Symmetric cells operating at RT with Li1.5Al0.5Ge1.5(PO4)3 electrolyte confirm the feasibility of the all-solid-state design

Li3V2(PO4)3 and Li3V1.9M0.1(PO4)3 (M = Fe, Al) samples were synthesized via spray-drying-assisted carbothermal solid-state reaction, and their structural and electrochemical properties were investigated by XRD, SEM, and galvanostatic charge/discharge. Li3V2(PO4)3, Li3V1.9Fe0.1(PO4)3, and Li3V1.9Al0.1(PO4)3 showed initial discharge capacities of 103.3 mAh g− 1, 107.6 mAh g− 1, and 105.6 mAh g− 1, respectively, in the all-solid-state symmetric batteries with Li1.5Al0.5Ge1.5(PO4)3 solid-state electrolytes at a rate of 7.5 mA g− 1. The enhanced discharge capacities of Fe and Al-doped Li3V2(PO4)3 could be attributed to the increased electrical conductivity induced by the introduction of Fe3 + or Al3 + trivalent ions into the V3 + sites and to the structural stabilization of the monoclinic Li3V2(PO4)3 by the spray-drying process.