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Influence of the Electrolyte Salt Concentration on the Rate Capability of Ultra‐Thick NCM 622 Electrodes
Author(s) -
Kremer Lea Sophie,
Danner Timo,
Hein Simon,
Hoffmann Alice,
Prifling Benedikt,
Schmidt Volker,
Latz Arnulf,
WohlfahrtMehrens Margret
Publication year - 2020
Publication title -
batteries and supercaps
Language(s) - English
Resource type - Journals
ISSN - 2566-6223
DOI - 10.1002/batt.202000098
Subject(s) - electrolyte , electrode , salt (chemistry) , conductivity , ionic conductivity , materials science , polarization (electrochemistry) , ion , chemistry , analytical chemistry (journal) , chromatography , organic chemistry
Abstract In traditional Li‐ion batteries, the electrolyte consists of a Li‐conducting salt dissolved in organic solvents at a concentration of ∼ 1 mol L −1 (1 M). In this work, we use increased LiPF 6 concentrations between 1 and 2.3 M to investigate the influence of the electrolyte salt concentration on the rate capability of ultra‐thick (49.5 mg cm −2 ) and thin (5.6 mg cm −2 ) NCM 622 electrodes, respectively. At higher electrolyte salt concentrations than 1 M, thin electrodes suffer from increased polarization, due to a higher viscosity and a reduced ionic conductivity. In contrast, by raising the salt concentration from 1 to 1.9 M the discharge capacity of ultra‐thick electrodes is increased by more than 50 % for current densities above 3 mA cm −2 , which significantly improves their rate capability. 3D microstructure resolved simulations revealed that this effect results from the mitigation of Li‐ion depletion in the electrolyte filled pore space of ultra‐thick electrodes.