Application of a cost-effective boron-based electrolyte additive in high-voltage lithium metal battery

Due to long-term operation under high voltage, the cathode of lithium metal battery undergoes parasitic reactions with the electrolyte, resulting in non-conductive polymers that severely affect the battery's electrochemical performance and kinetics. In addition, the safety performance of the battery is seriously compromised by severe lithium deposition on the lithium metal side. The use of electrolyte additives is one of the most cost-effective strategies for improvement. A low-cost boron-based additive bis(pinacolato)diboron (BDB) has been proposed in this work which has relatively high activity during battery charging and discharging. A protective cathode electrolyte interface (CEI) film was formed by BDB on the surface of NCM811 in advance to resist HF and solvent erosion. Furthermore, the solid electrolyte interface (SEI) film that BDB participates in on the lithium metal surface exhibits high ion conductivity and effectively inhibits the formation of lithium dendrites, thereby ensuring the safe operation of lithium metal batteries. The lithium metal battery utilizing BDB not only exhibits optimal electrochemical performance with a high cut-off voltage of 4.6 V, but also demonstrates potential for further development in the realms of rapid charging and discharging.