Sodium-Rich Vanadium-Based Polyanion Cathode Material for High Energy Density Sodium Ion Storage

NASICON-type Na3V2(PO4)3 (NVP) is a promising cathode material for sodium ion batteries (SIBs). However, replacing V with a low-cost, environmentally friendly metal ion is an immediate priority for NVP industrialisation. In this paper, we synthesize a sodium-rich vanadium-based polyanion cathode material by mechanochemical method. Na3.5V1.5Mn0.5(PO4)3/C (NVMP/C-0.5) shows excellent electrochemical performance and has almost no Jahn-Teller effect. The initial discharge capacity of NVMP/C-0.5 reaches 136.2 mAh g-1 at 0.1 C, and the voltage plateau reaches 3.5 V. NVMP/C-0.5 also exhibits excellent rate performance (96.4 mAh g-1 at 20 C) and long cycle performance (capacity retained 64.7% after 8000 cycles at 20 C). Ex-situ X-ray photoelectron spectroscopy (XPS) tests demonstrate that V3+/V4+, V4+/V5+ and Mn2+/Mn3+ redox pairs are all involved in redox reactions. Ex-situ X-ray diffraction (XRD) tests reveal that NVMP/C-0.5 has high structural reversibility and small volume change in charge-discharge reaction. The high energy density of NVMP/C-0.5//hard carbon full cell confirms the potential application of NVMP/C-0.5.

Keywords: NVMP/C-0.5, Ex-situ XRD, NVMP/C-0.5//hard carbon full cell, High energy density, Ex-situ XPS

Suggested Citation: Suggested Citation

Ding, Haiyang and Tao, Qingdong and Tang, Xin and Zhao, Haomiao and Zhang, Kaibo and Li, Jing, Sodium-Rich Vanadium-Based Polyanion Cathode Material for High Energy Density Sodium Ion Storage. Available at SSRN: https://ssrn.com/abstract=4329616 or http://dx.doi.org/10.2139/ssrn.4329616