Stabilized Co3+/Co4+ Redox Pair in In Situ Produced CoSe2−x– Derived Cobalt Oxides for Alkaline Zn Batteries with 10 000-Cycle Lifespan and 1.9–V Voltage Plateau

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Author(s)

  • Yongchao Tang
  • Xuejin Li
  • Haiming Lv
  • Dong Xie
  • Wenlong Wang

Detail(s)

Original languageEnglish
Article number2000892
Journal / PublicationAdvanced Energy Materials
Volume10
Issue number25
Online published19 May 2020
Publication statusPublished - 7 Jul 2020

Abstract

In aqueous alkaline Zn batteries (AZBs), the Co3+/Co4+ redox pair offers a higher voltage plateau than its Co2+/Co3+ counterpart. However, related studies are scarce, due to two challenges: the Co3+/Co4+ redox pair is more difficult to activate than Co2+/Co3+; once activated, the Co3+/Co4+ redox pair is unstable, owing to the rapid reduction of surplus Co3+ to Co2+. Herein, CoSe2−x is employed as a cathode material in AZBs. Electrochemical analysis recognizes the principal contributions of the Co3+/Co4+ redox pair to the capacity and voltage plateau. Mechanistic studies reveal that CoSe2−x initially undergoes a phase transformation to derived CoxOySez, which has not been observed in other Zn//cobalt oxide batteries. The Se doping effect is conducive to sustaining abundant and stable Co3+ species in CoxOySez. As a result, the battery achieves a 10 000-cycle ultralong lifespan with 0.02% cycle−1 capacity decay, a 1.9-V voltage plateau, and an immense areal specific capacity compared to its low-valence oxide counterparts. When used in a quasi-solid-state electrolyte, as-assembled AZB delivers 4200 cycles and excellent tailorability, a promising result for wearable applications. The presented effective strategy for obtaining long-cyclability cathodes via a phase transformation-induced heteroatom doping effect may promote high-valence metal species mediation toward highly stable electrodes.

Research Area(s)

  • alkaline zinc batteries, metal selenide derivatives, residual doping effect, ultralong cyclability, valence mediation

Citation Format(s)

Stabilized Co3+/Co4+ Redox Pair in In Situ Produced CoSe2−x– Derived Cobalt Oxides for Alkaline Zn Batteries with 10 000-Cycle Lifespan and 1.9–V Voltage Plateau. / Tang, Yongchao; Li, Xuejin; Lv, Haiming; Xie, Dong; Wang, Wenlong; Zhi, Chunyi; Li, Hongfei.

In: Advanced Energy Materials, Vol. 10, No. 25, 2000892, 07.07.2020.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal