Design of a hydrolysis‐supported coating layer on the surface of Ni‐rich cathodes in secondary batteries

Abstract

Summary The formation of Li4SiO4 (LSO) coating layer on LiNi0.88Co0.05Mn0.07O2 (LNCM) was achieved by incorporating a new tetraethyl orthosilicate (TEOS)‐dropping coating method. This concept includes the hydrolysis reaction of TEOS on the surface of Ni0.88Co0.05Mn0.07(OH)2 and the subsequent calcination process with lithium source to obtain LSO‐coated LNCM cathode materials successfully during the calcination process. This method provides the driving force for the formation of a more uniform and thin coating layer compared with the traditional wet‐chemical coating method. The bare LNCM and LSO‐coated LNCM showed similar capacity retention rates during room temperature (25°C) cycling, but the capacity retention of LSO‐LNCM (81.6% after 100 cycles) for the cycling test at elevated temperature was significantly increased compared with bare LNCM (63.69% after 100 cycles). Additionally, the Li‐ion accessibility of the coated LNCM electrode was improved by the existence of the Li‐containing coating materials, and the results of analysis by the galvanostatic intermittent titration technique (GITT) confirmed the better Li‐ion diffusivity of the coated sample. These results indicate the high possibility of this novel coating method for application in various materials for developing secondary batteries.

Boosting the electrochemical performance and moisture stability of O3-type NaNi1/3Fe1/3Mn1/3O2 cathodes using novel Na2MoO4 coatings prepared via a polyvinylpyrrolidone-anchored complex coating process

“…The specic capacity was determined by the electrochemical reaction of the cathode material; because NMO was not involved in this reaction, its presence in the coating layer did not contribute to the specic capacity. 45 Fig. 4b displays the CV curves of the pristine NFM and 1 wt% and 2 wt% NMO-NFM electrodes in the voltage range of 2.0-4.0 V at 0.1 mV s −1 .…”

“…The specific capacity was determined by the electrochemical reaction of the cathode material; because NMO was not involved in this reaction, its presence in the coating layer did not contribute to the specific capacity. 45…”