Insights into the stable and fast lithium storage performance of oxygen-deficient LiV3O8 nanosheets

Oxygen-deficient LiV(3)O(8)is considered as one of the promising cathode materials for lithium ion batteries (LIBs) because of its high cycling stability and rate capability. However, it is very difficult to control and study the content and position of V(4+)and oxygen vacancies in LiV3O8, and therefore the mechanism of improving electrochemical performance of LiV(3)O(8)is still unclear. Herein, we developed four LiV(3)O(8)nanosheets with different V(4+)and oxygen vacancy contents and positions. The physicochemical and lithium storage properties indicate that the V(4+)and oxygen vacancies in the surface layer increase the contribution of pseudocapacitive lithium storage on the nanosheet surface. The V(4+)and oxygen vacancies in the lattice improve the electrical conductivity of LiV3O8, and enhance the phase transformation and lithium ion diffusion rates. By adjusting the content of V(4+)and oxygen vacancies, we obtained an oxygen-deficient LiV(3)O(8)nanosheet which maintained more than 93% of the initial reversible capacity after 300 cycles at 5,000 mA center dot g(-1). The V(4+)and oxygen vacancies play an important role in improving the stability and rapidity of lithium storage. This work is helpful to understand the stable and fast lithium storage mechanism of oxygen-deficient LiV3O8, and might lay a foundation for further studies of other oxygen-deficient metal oxide electrodes for long-life and high-power LIBs.

Automated summary

The study demonstrated the crucial roles of V(4+) and oxygen vacancies in LiV3O8 nanosheets in enhancing the stability and rapidity of lithium storage, and adjusting their contents can lead to improved electrochemical performance.