Unconventional irreversible structural changes in a high-voltage Li-Mn-rich oxide for lithium-ion battery cathodes

JOURNAL OF POWER SOURCES

卷:283

Article

Mohanty, Debasish¹  Sefat, Athena S.²  Payzant, E. Andrew³  Li, Jianlin¹  Wood, David L., III¹  Daniel, Claus¹ 

[1] Oak Ridge Natl Lab, Energy & Transportat Sci Div, Oak Ridge, TN 37831 USA

[2] Oak Ridge Natl Lab, Mat Sci & Technol Div, Oak Ridge, TN 37831 USA

[3] Oak Ridge Natl Lab, Chem & Engn Mat Div, Oak Ridge, TN 37831 USA

关键词: Lithium rich;    Structural transformation;    Spinel;    High-energy-density lithium-ion batteries;    Magnetic frustration;   

DOI  :  10.1016/j.jpowsour.2015.02.087

来源: Elsevier

【 摘 要 】

Making all-electric vehicles (EVs) commonplace in transportation applications will require affordable high-power and high-energy-density lithium-ion batteries (LIBs). The quest for suitable cathode materials to meet this end has currently plateaued with the discovery of high-voltage (>= 4.7 V vs. Li+), high capacity (similar to 250 mAh/g) lithium manganese-rich (LMR) layered composite oxides. Despite the promise of LMR oxides in high-energy-density LIBs, an irreversible structural change has been identified in this work that is governed by the formation of a 'permanent' spin-glass type magnetically frustrated phase indicating a dominant AB(2)O(4) (A = Li, B = Mn) type spinel after a short-term lithium deintercalation (charging) and intercalation (discharging) process. Furthermore, reduction of transition metal (Mn) ions from the 4+ state (pristine LMR) to 3+ (cycled LMR), which alters the intercalation redox chemistry and suggests the presence of 'unfilled' lithium vacancies and/or oxygen vacancies in the lattice after cycling, has presented a major stumbling block. These situations result in both loss of capacity and fading of the voltage profile, and these combined effects significantly reduce the high energy density over even short-term cycling. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

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