Boosting Li-Ion Diffusion Kinetics of Na2Ti6-xMoxO13 via Coherent Dimensional Engineering and Lattice Tailoring: An Alternative High-Rate Anode.

Abstract

Featured with an exposed active facet, favorable ion diffusion pathway, and tailorable interfacial properties, low-dimensional structures are extensively explored as alternative electroactive materials with game-changing redox properties. Through a stepwise "proton exchange-insertion-exfoliation" procedure, in this article, we develop Na2Ti6-xMoxO13 (NTMO) nanosheets with weakened out-of-plane bonding and in-plane Mo6+ doping of the tunnel structure. Real-time phase tracking of the laminated NTMO structures upon the lithiation/delithiation process suggests mitigated lattice variation; meanwhile, the kinetics simulation shows a mitigated Li-ion diffusion barrier along the [010] orientation. At an industrial-level areal capacity loading (2.5 mAh cm-2), the NTMO electrode maintains robust cycling endurance (91% capacity retention for 2000 cycles) even at 40 C, as well as the high energy/power densities in the as-constructed NTMO||LiFePO4 full cell prototype. The dimensional and lattice modifications presented in this study thus encourage further exploration of the tailored cation diffusion pathway for the construction of fast-charging batteries.