Solvation Structure Modulation Of High-Voltage Electrolyte For High-Performance K-Based Dual-Graphite Battery.

Abstract

Due to the advantages of dual-ion batteries (DIBs) and abundant resources, potassium-based dual-carbon batteries (K-DCBs) have wide application prospects. However, conventional carbonate ester-based electrolyte systems have obvious drawbacks such as poor oxidation resistance and difficulty in sustaining the anion intercalation process at high voltages, which seriously affect the capacity and cycle performance of K-DCBs. Therefore, a rational design of more efficient novel electrolyte systems is urgently required to realize high-performance K-DCBs. Herein, we report a solvation structure modulation strategy for the K-DCB electrolyte systems. Consequently, substantial K+ ion storage improvement at the graphite anode and enhanced FSI- intercalation capacity at the graphite cathode are successfully realized simultaneously. As a proof-of-concept, the assembled K-DCB exhibited a discharge capacity of 103.4 mAh g-1 , and after 400 cycles, approximately 90% capacity retention was observed. Moreover, the energy density of the K-DCB full cell reached 157.6Wh kg-1 , which is the best performance in reported K-DCBs till date. This study demonstrates the effectiveness of solvation modulation in improving the performance of K-DCBs. This article is protected by copyright. All rights reserved.