Interface-rich mixed P2 + T phase NaxCo0.1Mn0.9O2 (0.44 ≤ x ≤ 0.7) toward fast and high capacity sodium storage. Issue 15 (28th March 2018)

• Record Type: Journal Article
• Authors: Gao, Guofeng; Tie, Da; Ma, Hao; Yu, Haijun; Shi, Shanshan; Wang, Bo; Xu, Shengming; Wang, Linlin; Zhao, Yufeng
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 15(2018)
• Page Start: 6675
• Page End: 6684
• Publication Date: 2018-03-28
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c8ta00206a
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : This work reports a novel design of mixed P2 + T phase Na x Co0.1 Mn0.9 O2 for high performance sodium storage, whereby the T phase offers fast Na ion diffusivity and excellent structural stability, and the P2–T phase interface offers additional channels and extra sites for charge transfer and charge storage. Abstract : In this work, we report a novel design of mixed P2 + T phase Na x Co0.1 Mn0.9 O2 (0.44 ≤ x ≤ 0.7) with interface rich characteristics for high performance sodium storage, whereby the tunneled T phase offers fast Na ion diffusivity and excellent structural stability, the layered P2 phase contributes to high specific capacity, and the P2 + T phase interface offers additional channels and active sites for charge transfer and excess charge storage. Consequently, the as-prepared Na x Co0.1 Mn0.9 O2 (0.44 ≤ x ≤ 0.7) demonstrates an excellent discharge capacity of 219 mA h g −1 at a current rate of 0.1C (1C = 176 mA g −1 ), and retains 117 mA h g −1 even at a high rate of 5C. This outstanding performance is significantly superior to that of pure T-type Na0.44 Co0.1 Mn0.9 O2 and P2-type Na0.7 Co0.1 Mn0.9 O2, and also outperforms state-of-the-art manganese-based cathodes. The kinetic analysis indicates the drastically improved Na + diffusion coefficient of the P2 + T phase, which is 6 and 200 times that of the pure T and P phases, respectively. The good reversibility and structural stability is evidenced through an ex situ XRD study.