Ion Co-storage in Porous Organic Frameworks through On-site Coulomb Interactions for High Energy and Power Density Batteries

Abstract

Fast and continuous ion insertion is blocked in the common electrodes operating with widely accepted single-ion storage mechanism, primarily due to Coulomb repulsion between the same ions. It results in an irreconcilable conflict between capacity and rate performance. Herein, we designed a porous organic framework with novel multiple-ion co-storage modes, including PF6−/Li+, OTF−/Mg2+, and OTF−/Zn2+ co-storage. The Coulomb interactions between cationic and anionic carriers in the framework can significantly promote electrode kinetics, by rejuvenating fast ion carrier migration toward framework interior. Consequently, the framework via PF6−/Li+ co-storage mode shows a high energy density of 878 Wh kg−1 cycled more than 20 000 cycles, with an excellent power density of 28 kW kg−1 that is already comparable to commercial supercapacitors. The both greatly improved energy and power densities via the co-storage mode may pave a way for exploring new electrodes that are not available from common single-ion electrodes.