A truncated octahedral Li-rich LiMn2O4 electrode for long-life electrochemical lithium extraction from brine

Since the low raw cost, environmentally friendly and superior capacity performance, spinel LiMn 2 O 4 is widely considered as a suitable electrode material for electrochemical lithium extraction from salt-lake brine. However, the inherent problem of manganese dissolution inhibits its structural stability during long-term lithium recovery process. In this work, a series of Li-rich spinel Li 1+x Mn 2-x O 4 were prepared, and their cycle stability and Li + diffusion coefficient are significantly improved via Li-rich modification. Specially, the Li 1.05 Mn 1.95 O 4 shows the optimal lithium-extraction performance, with a specific capacity of 108 mAh g −1 ​at 0.2 ​A ​g −1 and high retention rate of 82.5 ​% after 100 cycles. In the Li 1.05 Mn 1.95 O 4 ||Ag system, Li ​ + ​extraction capacity per cycle can reach 1.81 mmol Li g LMO −1 with high separation coefficients of α Li-Na ​= ​4432.4, α Li-K ​= ​160.56, α Li-Mg ​= ​481.31. Therefore, this study provides an effective Li-rich strategy to improve manganese-based electrode materials with high recovery stability for lithium extraction.