Premium
Surface Mn Oxidation State Controlled Spinel LiMn 2 O 4 as a Cathode Material for High‐Energy Li‐Ion Batteries
Author(s) -
Jeong Minseul,
Lee MinJoon,
Cho Jaephil,
Lee Sanghan
Publication year - 2015
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201500440
Subject(s) - spinel , materials science , stoichiometry , coating , cathode , cobalt , manganese , lithium (medication) , chemical engineering , metallurgy , composite material , chemistry , medicine , engineering , endocrinology
Spinel lithium manganese oxide (LiMn 2 O 4 ) has attracted much attention as a promising cathode material for large‐scale lithium ion batteries. However, its continuous capacity fading at elevated temperature is an obstacle to extended cycling in large‐scale applications. Here, surface Mn oxidation state controlled LiMn 2 O 4 is synthesized by coating stoichiometric LiMn 2 O 4 with a cobalt‐substituted spinel, for which stoichiometric LiMn 2 O 4 is used as the starting material and onto which a Li x Mn y Co z O 4 layer is coated from an acetate‐based precursor solution. In the coated material, the concentrations of both cobalt and Mn 4+ ions vary from the surface to the core. the former without any lattice mismatch between the coating layer and host material. Cycle tests are performed under severe conditions, namely, high temperature and intermittent high current load. During the first discharge cycle at 7 C and 60 °C, a high energy and power density are measured for the coated material, 419 and 3.16 Wh kg −1 , respectively, compared with 343 and 3.03 Wh kg −1 , respectively, for the bare material. After 65 cycles under severe conditions, the coated material retains 82% and ≈100% of the initial energy and power density, respectively, whereas the bare material retains only ≈68% and ≈97% thereof.