P2–Na 2/3 Ni 1/3 Mn 5/9 Al 1/9 O 2 Microparticles as Superior Cathode Material for Sodium-Ion Batteries: Enhanced Properties and Mechanism via Graphene Connection

作者：Xiaohua Zhang, Wei‐Lin Pang, Fang Wan, Jin‐Zhi Guo, Hong‐Yan Lü, Jin-Yue Li, Yueming Xing, Jingping Zhang, Xing‐Long Wu · 发表于：ACS Applied Materials & Interfaces · 年份：2016 · DOI：10.1021/acsami.6b03944 · 被引用次数：185 · 研究领域：Advancements in Battery Materials、Advanced Battery Materials and Technologies、Supercapacitor Materials and Fabrication

As a promising alternative for lithium ion batteries, room-temperature sodium ion batteries (SIBs) have become one significant research frontier of energy storage devices although there are still many difficulties to be overcome. For the moment, the studies still concentrate on the preparation of new electrode materials for SIBs to meet the applicability. Herein, one new P2-Na2/3Ni1/3Mn5/9Al1/9O2 (NMA) cathode material is successfully prepared via a simple and facile liquid-state method. The prepared NMA is layered transition metal oxide, which can keep stable crystal structure during sodiation/desodiation as demonstrated by the ex situ X-ray diffraction, and its electrochemical properties can be further enhanced by connecting the cake-like NMA microparticles with reduced graphene oxide (RGO) using a ball milling method. Electrochemical tests show that the formed RGO-connected NMA (NMA/RGO) can deliver a higher reversible capacity of up to 138 mAh g(-1) at 0.1 C and also exhibit a superior high-rate capabilities and cycling stability in comparison to pure NMA. The much improved properties should be attributed to the reduced particle size and improvement of electrical conductivity and apparent Na(+) diffusion due to RGO incorporation, which is comprehensively verified by the electrochemical technologies of galvanostatic intermittent titration technique, electrochemical impedance spectroscopy and cyclic voltammetry at various scan rate as well as ex-situ X-ray diffraction studi...