Cation mixing in Wadsley-Roth phase anode of lithium-ion battery improves cycling stability and fast Li⁺ storage

Developing advanced electrode materials with high stability and high ion-diffusion rate is vital for the success of high-rate lithium-ion batteries (LIBs). However, the commonly used modification strategies such as carbon coating, nanoarchitecture engineering, and introducing oxygen vacancies are unavoidably meeting with the problems of high cost and complicated preparation process. Herein, we report cation-mixing effect enhanced fast Li⁺ storage in Wadsley-Roth phase Fe-Ti-Nb oxide (FTNO) materials by a facile solution combustion method. Co-existence of Fe³⁺ and Ti⁴⁺ in the crystallographic shear structure leads to enhanced cation-mixing effect with cations short-range order (SRO) in FTNO materials, thus resulting in outstanding capabilities of fast Li⁺ storage/diffusion, robust structure and low charge transfer resistance compared with the analogues of FeNb₁₁O₂₉ and Ti₂Nb₁₀O₂₉. Consequently, a high-capacity retention of 71.8% is achieved upon 10 000 cycles at 10 C. Most importantly, the feasibilities of FTNO are also systematically verified in various practical electrochemical energy storage devices containing conventional lithium-ion full battery (FTNOǁLiFePO₄), high-power lithium-ion hybrid capacitor [FTNOǁactive carbon (AC)], and novel dual-ion battery [FTNOǁmesocarbon microbeads (MCMB)]. It is worth noting that the FTNOǁMCMB with high output voltage of 3 V delivers a capacity of 105.7 mAh g⁻¹, implying a great potential of FTNO applied in dual-ion batteries.