Theoretical capacity achieved in a LiMn0.5Fe0.4Mg0.1BO3 cathode by using topological disorder

Jae Chul Kim, Dong Hwa Seo, Gerbrand Ceder

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

Simple borates are attractive cathodes for lithium-ion batteries due to two main reasons: covalently bonded anions provide operating stability through suppressed oxygen loss, and the borate group (BO3) possesses the highest theoretical specific capacity for one-electron polyanion systems. In this work, we demonstrate an electrochemically superior lithium borate (LiMn0.5Fe0.4Mg0.1BO3) that delivers a near theoretical capacity (98%) of 201 mA h g-1 at C/50, an improved rate capability of 120 mA h g-1 at 1 C, and good capacity retention. Using ab initio modeling, the superior Li intercalation activity is explained by both stabilization of the delithiated state and increased topological cation disorder, which counter-intuitively facilitates Li transport. Our results indicate that through engineering of defect chemistry, the basic mechanism can be modified from one-dimensional to three-dimensional conduction, thereby improving kinetics. Combined with the inherent stability of the borate group, the enhanced electrochemical properties should reinvigorate search in borate chemistry for new safe and high-energy cathode materials.

Original languageEnglish
Pages (from-to)1790-1798
Number of pages9
JournalEnergy and Environmental Science
Volume8
Issue number6
DOIs
StatePublished - 1 Jun 2015

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