Here, three types of surface coatings based on adsorption of organic aromatic acids or their Li salts are applied as functional coating substrates to engineer the surface properties of high voltage LiNi0.5Mn1.5O4 (LNMO) spinel cathodes. The materials used as coating include 1,3,5-benzene-tricarboxylic acid (trimesic acid [TMA]), its Li-salt, and 1,4-benzene-dicarboxylic acid (terephthalic acid). The surface coating involves simple ethanol liquid-phase mixing and low-temperature heat treatment under nitrogen flow. In typical comparative studies, TMA-coated (3–5%) LNMO cathodes deliver >90% capacity retention after 400 cycles with significantly improved rate performance in Li-coin cells at 30 °C compared to uncoated material with capacity retention of ≈40%. The cathode coating also prevents the rapid drop in the electrochemical activity of high voltage Li cells at 55 °C. Studies of high voltage full cells containing TMA coated cathodes versus graphite anodes also demonstrate improved electrochemical behavior, including improved cycling performance and capacity retention, increased rate capabilities, lower voltage hysteresis, and very minor direct current internal resistance evolution. In line with the highly positive effects on the electrochemical performance, it is found that these coatings reduce detrimental transition metal cations dissolution and ensure structural stability during prolonged cycling and thermal stability at elevated temperatures.
|State||Published - 20 Oct 2022|
Bibliographical noteFunding Information:
This work was supported by the German BASF SE and the Israeli Committee for Higher Education within the INREP project framework.
© 2022 Wiley-VCH GmbH.
- LiNi Mn O (LNMO) spinel
- benzene carboxylic acids
- high-voltage cathodes
- lithium-ion batteries
- surface coatings