Cover Picture: Investigation of the Decomposition Mechanism of Lithium Bis(oxalate)borate (LiBOB) Salt in the Electrolyte of an Aprotic Li–O2 Battery (Energy Technol. 4/2014) (page 305)
Kah Chun Lau, Jun Lu, John Low, Du Peng, Huiming Wu, Hassan M. Albishri, D. Abd Al-Hady, Larry A. Curtiss and Khalil Amine
Article first published online: 17 APR 2014 | DOI: 10.1002/ente.201490006
Electrolyte Stability in Li–Air Batteries. A key challenge for the development of aprotic Li–O2 (Li–air) batteries is the stability of salts and solvents during charging and discharging. The free-energy surfaces of the lithium bis(oxalate) borate (LiBOB) salt interacting with lithium peroxide (Li2O2) are studied by first-principles simulations to determine possible mechanisms for decomposition. The simulations were performed by using density functional theory (DFT), ab initio molecular dynamics, and metadynamics simulations as described in the Full Paper by scientists from Argonne National Laboratory on page 348. The theoretical findings suggest that the chemical decomposition of LiBOB in the electrolyte leads to the formation lithium oxalate during the operation of a Li–O2 cell. According to DFT calculations, the formation of lithium oxalate as the reaction product is exothermic and therefore is thermodynamically feasible. The decomposition was confirmed by experimental measurements. This reaction is independent of the solvent used in the Li–O2 cell, and therefore LiBOB is probably not suitable to be used as salt in Li–O2 cell electrolytes. The study illustrates how simulations can be used to help determine the causes of battery failure and help in the design of new electrolytes.