In the development of high-voltage lithium-ion batteries, unwanted interfacial side reactions between delithiated cathode materials and liquid electrolytes pose a formidable challenge that needs to be urgently resolved. In this study, as a simple and effective approach to improve cell performance and thermal stability of high-voltage cells, we demonstrate direct surface modification of a cathode by UV-cured nanothickness poly(ethylene glycol diacrylate) (PEGDA) gel polymer electrolyte (GPE). Herein, the UVcrosslinking of EGDA oligomers is conducted directly on as-formed cathode (LiCoO2 (LCO) is chosen as a model system), instead of application to LCO powders. This unusual coating process allows the successful formation of the conformal PEGDA nanocoating layer on the LCO surface without disrupting the preformed physical architecture of the LCO cathode (specifically, electronic networks and porous structure to be filled with liquid electrolyte). Owing to the structural novelty, the PEGDA-coated LCO cathode improves the cycling performance of high-voltage (=4.4 V) cells and suppresses the exothermic reaction between the delithiated LCO and liquid electrolyte, as compared to the pristine LCO cathode. These results underline that the conformal PEDGDA nanocoating layer proposed herein acts as a new ion-conductive protection film that effectively mitigates the undesired interfacial side reactions.
Bibliographical noteFunding Information:
This research was supported by the MSIP (Ministry of Science, ICT&Future Planning), Korea, under the C-ITRC(Convergence Information Technology Research Center) support program (NIPA-2013-H0301-13-1009) supervised by the NIPA (National IT Industry Promotion Agency). This work was also supported by the National Research Foundation of Korea Grant funded by the Korean Government (MEST) (NRF-2009-C1AAA001-2009-0093307).
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)