期刊
JOURNAL OF POWER SOURCES
卷 321, 期 -, 页码 135-142出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.jpowsour.2016.05.002
关键词
Alkaline battery; Manganese dioxide; Zinc; Spinel; Proton insertion; Operando diffraction
资金
- Laboratory Directed Research and Development Program of Brookhaven National Laboratory (LDRD-BNL) [DE-AC02-98CH10866]
- U.S. Department of Energy
- U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-AC02-98CH10886]
The rechargeability of gamma-MnO2 cathodes in alkaline batteries is limited by the formation of the [Mn-2]O-4 spinels ZnMn2O4 (hetaerolite) and Mn3O4 (hausmannite). However, the time and formation mechanisms of these spinels are not well understood. Here we directly observe gamma-MnO2 discharge at a range of reaction extents distributed across a thick porous electrode. Coupled with a battery model, this reveals that spinel formation occurs at a precise and predictable point in the reaction, regardless of reaction rate. Observation is accomplished by energy dispersive X-ray diffraction (EDXRD) using photons of high energy and high flux, which penetrate the cell and provide diffraction data as a function of location and time. After insertion of 0.79 protons per gamma-MnO2 the alpha-MnOOH phase forms rapidly. alpha-MnOOH is the precursor to spinel, which closely follows. ZnMn2O4 and Mn3O4 form at the same discharge depth, by the same mechanism. The results show the final discharge product, Mn3O4 or Mn(OH)(2), is not an intrinsic property of gamma-MnO2. While several studies have identified Mn(OH)(2) as the final gamma-MnO2 discharge product, we observe direct conversion to Mn3O4 with no Mn(OH)(2). (C) 2016 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据