Nonmetal (S or Se)-Bridged Core Shell Electrodes for Promoting Electrochemical Performance

To meet strategic applications, rational design of advanced electrochemical materials would solve the poor electrochemical performance of core-shell electrodes caused by the weak interfacial interaction between core and shell. Herein, two novel core-shell electrodes LCCH-S@PBAs and LCCH-Se@PBAs are fabricated with a nonmetal (S or Se) bridging the core and shell. Electrochemical tests show that the as-synthesized electrodes, especially LCCH-S@PBAs, present higher mass-specific capacitance with 10.1 C cm(-2) at 1 mA cm(-2), which is much better than that of PBA-based homologs. Experimental results and theoretical calculations show that the bridging S or Se in the interface, not only tune electronic nature of the d-states of metal ions in core and shell, but also form ionic bonds (M-1(LCCH)-S-M-2(PBAs) and M-1(LCCH)-Se-M-2(PBAs)) which facilitates the transmission of electrons, thus making a substantial enhancement of electrochemical performance via a dynamically more favorable pathway. The comparison with LCCH-C@PBAs, in which the rGO is connected with core and shell by Van der Waals' forces, also suggests the outstanding role of ionic bonds for electrochemical performance. This work proves that nonmetal bridging structures make a great contribution for enhanced electrochemical performance and demonstrates the large space to modulate the nonmetal bridging status for core-shell structures in electrochemical materials.

Automated summary

Rational design of advanced electrochemical materials using nonmetal bridging between core and shell can solve the issue of weak interfacial interaction and improve electrochemical performance. This study fabricates two novel core-shell electrodes and demonstrates the crucial role of nonmetal bridging in enhancing electrochemical performance.