English
The demand for higher energy density is rapidly increasing, and the development of high-voltage all solid state lithium batteries (ASSLBs) has become crucial. However, most existing solid electrolytes (SE) still cannot operate stably at high voltages. Here, we report a series of lithium fluoride tantalum oxychloride (LTOC-F) as amorphous SE for high-voltage ASSLB. The optimized LTOC-10% F SE exhibits significantly improved high voltage stability and high ion conductivity of 2.3 mS cm-1 at 25 ° C. The ASSLB using LCO cathode and LTOC-10% F SE can achieve a high capacity of 180 mAh g-1, with a cut-off voltage of 4.5 V and a high capacity retention rate of 81% after 300 cycles. In addition, the potential mechanisms for enhancing performance are believed to be the electrochemical window that SE essentially expands and the in-situ formation of LiF rich cathode electrolyte interface (CEI). Overall, this work provides a fluorination strategy for high-pressure ASSLB and insights for the analysis of amorphous SE and CEI.
