Microstructural Effects on Electronic Charge Transfer in Li-Ion Battery Cathodes

An analytical model for the assessment of Li-ion battery cathode microstructure is presented. This model focuses on electronic transport within an extended surface of conductive material subject to charge transfer governed by linear surface charge transfer kinetics. In applying this approach the model presented allows for the prompt assessment of the impacts of microstructural morphology on electrode performance, thus providing for facilitated design of more deterministic electrode microstructures. It is demonstrated that the analytical approach developed can reproduce experimentally observed trends in measured electrode resistance and capture the effects of electrode microstructural morphology. The role of microstructural morphology is addressed for three common positive electrode chemistries: LiCoO2, LiFePO4 and LiMn2O4. For the first two of these electrode chemistries the impacts of both solid phase and surface morphology may be significant due to electronic transport losses dominating over charge transfer kinetics. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.070205jes] All rights reserved.