Layered Perovskite Lithium Yttrium Titanate as a Low‐Potential and Ultrahigh‐Rate Anode for Lithium‐Ion Batteries

Abstract

AbstractGraphite, as the dominant anode for commercial lithium‐ion batteries, features sluggish electrochemical kinetics and low potential close to lithium deposition, leading to poor rate capability and safety issues. Although titanium‐based oxides have received considerable attention, each alternative demonstrates unsatisfactory trade‐offs between capacity, operating potential, rate capability, and lifespan. Here, submicrometer‐sized lithium yttrium titanate (LYTO) is synthesized through facile sol–gel and ion‐exchange reactions. With an average operating potential of 0.3 V versus Li+/Li, the LYTO anode demonstrates a high specific capacity of 236 mAh g–1 and durable cycling performance of 98% capacity retention after 3000 cycles. Impressively, without additional modification, a high‐rate capability is achieved under a current density range from 0.5 C to 100 C (1 C = 200 mA g–1), e.g., delivering 112 and 87 mAh g–1 at 60 C and 100 C, respectively. Comprehensive characterizations and computational simulations reveal reversible solid‐solution reactions occurring in the LYTO framework with little lattice change and fast 2D Li+ mobility achieved due to a low diffusion energy barrier. After incorporation with a LiFePO4 cathode, the energy density of the as‐fabricated full cell reaches 2.4 times that of Li4Ti5O12/LiFePO4 full cell. The double characteristics of LYTO provide a fresh identification for high‐performance anodes.