Stabilizing Na0.7MnO2 cathode for Na-ion battery via a single-step surface coating and doping process

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

19 Scopus Citations
View graph of relations

Related Research Unit(s)

Detail(s)

Original languageEnglish
Pages (from-to)106-112
Journal / PublicationJournal of Power Sources
Volume391
Online published30 Apr 2018
Publication statusPublished - 1 Jul 2018

Abstract

P2-type Na0.7MnO2, with high capacity and excellent Na ion conductivity, is a promising cathode material for Na-ion batteries. However, its rapid capacity decay upon repeated cycles restricts its practical application. In this study, we demonstrate a facile method to surface coat and dope P2-Na0.7MnO2 with a P2-Na0.7Ni0.33Mn0.67O2 layer in a single step to enhance its cycle stability. The coating suppresses the dissolution of Mn ions into electrolyte, and the Ni dopant suppresses orthorhombic distortion, inhibits Na+/vacancy ordering and improves structural stability upon cycling. As a consequence, the coating enhances capacity retention from 62.2% (Na0.7MnO2) to 87.7% (Na0.7MnO2/20 wt% Na0.7Ni0.33Mn0.67O2) over 50 cycles, and from 20.7% (Na0.7MnO2) to 68.9% (Na0.7MnO2/20 wt% Na0.7Ni0.33Mn0.67O2) over 100 cycles without sacrificing the initial discharge capacity. In addition, the air-stable Na0.7Ni0.33Mn0.67O2 surface layer protects Na0.7MnO2 against air exposure.

Research Area(s)

  • Air exposure, Cathode, Cycle stability, Na-ion battery, Surface coating and doping