Δ-VOPO4 nanosheet with intrinsic V4+ defective as high-performance cathode for sodium-ion battery. (September 2021)

• Record Type: Journal Article
• Authors: Zhang, L.; Hu, X.; Wu, Y.; Gao, Y.; Lin, C.; Dong, C.; Li, G.; Xu, F.; Zhang, S.; Zhang, K.
• Is Part Of: Materials today energy. Volume 21(2021)
• Publication Date: 2021-09
• Subjects: Energy storage -- Vanadium phosphates -- Cathode -- Defect -- Phase; Energy development -- Periodicals; Energy industries -- Periodicals; Power resources -- Periodicals; Energy policy -- Periodicals; Energy development; Energy industries; Energy policy; Power resources; Electronic journals; Periodicals; 621.042
• DOI: 10.1016/j.mtener.2021.100756
• Languages: English
• ISSNs: 2468-6069

Abstract

Abstract: Transition metal phosphates have become of great interest as cathode materials for rechargeable ion batteries because of their low cost and environmental friendliness, but suffer from low-intrinsic conductivity. Here, we report that a δ phase VOPO4 (δ-VPO) nanosheets with intrinsic V 4+ defect, can deliver a specific capacity of 130 mA h/g at 0.2 C (1 C = 166 mA/g) with 75% capacity retention after 500 cycles as a cathode of sodium-ion batteries (SIBs), which is superior to previously reported α-VPO as well as sodiated VPO counterparts. Our results demonstrate that the high V 4+ defect concentration of VPO is responsible for the better high-rate performance because of enhanced conductivity and reduced redox polarization, while δ-VPO enabling high cycling stability resulting from the limited expansion of the lateral size. This work offers a potentially alternative cathode material with controllable phases and defects toward high-performance SIBs. Graphical abstract: Image 1 Highlights: A δ phase VOPO4 (δ-VPO) is successfully synthesized. The intrinsic V 4+ defects are controlled. The high V 4+ defect concentration of VPO is responsible for the better performance. An optimized δ-VPO can deliver a specific capacity of 130 mA h/g at 0.2 C.