American Chemical Society
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Realizing the Multi-electron Reaction in the Na3V2(PO4)3 Cathode via Reversible Insertion of Dihydrogen Phosphate Anions

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journal contribution
posted on 2021-12-28, 17:09 authored by Qiao Ni, Qiubo Guo, Haixia Ren, Ying Bai, Chuan Wu
Dual-ion battery (DIB) is an up-and-coming technology for the energy storage field. However, most of the current cathodes are still focused on the graphite hosts, which deliver a limited specific capacity. In this work, we demonstrated for the first time that H2PO4 can be used as the charge carrier for Na3V2(PO4)3 under an aqueous electrolyte, which enabled the V3+/V4+ and V4+/V5+ multielectron reactions in the Na3V2(PO4)3 electrode. The fabricated aqueous DIB delivers a high average voltage of ∼0.75 V (vs Ag/AgCl) and a high capacity of 280.7 mA h g–1. Moreover, the formed V5+-based novel cathode exhibits a capacity of 170.2 mA h g–1 in an organic sodium-ion battery. This study may open a new direction for fabricating high-voltage electrodes through the design of DIBs.