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 10000 cycles at 10C. Most importantly, the feasibilities of FTNO are also systematically verified in various practical electrochemical energy storage devices containing conventional lithium-ion full battery (FTNO parallel to LiFePO4), high-power lithium-ion hybrid capacitor [FTNO parallel to active carbon (AC)], and novel dual-ion battery [FTNO parallel to mesocarbon microbeads (MCMB)]. It is worth noting that the FTNO parallel to MCMB with high output voltage of 3V delivers a capacity of 105.7mAh g(-1), implying a great potential of FTNO applied in dual-ion batteries.

Automated summary

The study demonstrates that the cation-mixing effect can be enhanced by introducing a coexistence of Fe3+ and Ti4+ in the structure of Wadsley-Roth phase Fe-Ti-Nb oxide (FTNO) materials, leading to improved storage and diffusion performance in high-rate lithium-ion batteries. This material shows significant potential in various practical electrochemical energy storage devices.