Metastable V2O3 embedded in 2D N-doped carbon facilitates ion transport for stable and ultrafast sodium-ion storage

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2022-02, Vol.430, p.131156, Article 131156
• Main Authors: Qin, Zhongzheng, Zhou, Xin, Hu, Yongyuan, Pei, Jian, Chen, Gang
• Format: Article
• Language: English
• Subjects: AIMD calculations; Embedded structure; Metastable V2O3; N-doped carbon; Sodium-ion batteries
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.131156

A metastable V2O3 embedded in N-doped carbon nanosheets (c-V2O3@NC) is synthesized via a simple molten salt method. Benefiting from the novel metastable structure and multiple modifications, c-V2O3@NC shows enhanced ion diffusion kinetics, robust structure and improved conductivity, resulting in ultralong cycle life and ultrahigh rate capability for sodium-ion storage. [Display omitted] •Metastable cubic V2O3 embedded in N-doped carbon nanosheets (c-V2O3@NC) is synthesized.•AIMD calculations reveal the enhanced Na+ diffusion coefficient of metastable V2O3.•Simultaneous multiple modifications further improve the Na+ storage performance.•The c-V2O3@NC exhibits ultralong cycle life and ultrahigh rate capability. V2O3 is a promising candidate for sodium-ion batteries (SIBs) anode. Compared with common rhombohedral V2O3, cubic V2O3 is a unique metastable phase with ordered oxygen vacancies and high energy state, but lacks study in the field of electrochemical energy storage. Herein, a metastable cubic V2O3 embedded in N-doped carbon nanosheets (c-V2O3@NC) is synthesized by a simple molten salt method with urea assisted. Ab initio molecular dynamics calculations demonstrate that cubic V2O3 possesses reduced Na+ diffusion activation energy. Benefiting from the novel metastable structure and multiple modifications, the c-V2O3@NC shows enhanced ion diffusion kinetics, robust structure and improved conductivity. As a consequence, the c-V2O3@NC exhibits high specific capacity, ultralong cycle life and ultrahigh rate capability (274 mAh g−1 even after 3000 cycles at 5 A g−1) as anode material for SIBs. This work shows a feasible synthesis and synchronous modification for metastable materials to electrical energy storage applications.