科研之友
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摘要
Insufficient areal energy density along with unstable delivery, resulting from a linearly sloped time-voltage response rooting in redox-free/surface-redox operating mechanisms severely restricts the application scenarios of micro-supercapacitors. Herein, by coupling silver nanowires (AgNWs) between MXene interlayers with the help of bacterial cellulose (BC) as bio-dispersant toward MXene/AgNWs&BC hybrid cathode to pair with Zn anode, a novel Zn2+-Cl- dual-ions micro-redox capacitor (MRC) employing polyacrylamide/ZnCl2 + NH4Cl hydrogel electrolyte is first present. The introduced AgNWs nanopillars alleviate the MXene nanosheets restacking to facilitate Cl- transfer kinetics, and concurrently strengthen the charge storage capacity and output stability benefiting from a flat discharge plateau stemming from the extra phase transition behavior (Ag &double left right arrow AgCl). Thus, an appealing dual energy storage mechanism, featuring i) expedited Cl- diffusion involved de/intercalation and ii) reversible solid-to-solid conversion of Ag/AgCl redox couple confined between MXene interlayers, is established and revealed by in situ XRD/Raman analyses. Consequently, remarkably boosted areal energy density up to 227 mu Wh cm(-2) along with significantly improved output stability and suppressed notorious self-discharge behavior, are achieved in the resultant MRC. This work provides a brand new strategy for designing innovative MXene-based MRC featuring a hybrid charge storage mechanism of ions-intercalation and phase conversion to simultaneously realize high and steady energy output.
