The wider application of conventional
electrochemical double-layer
supercapacitors is limited by severe self-discharge. Current strategies
for tackling self-discharge are mainly focused on each specific component
of the device, while a general approach based on configuration design
from the device level is largely unknown. Herein, we report a conjugated
supercapacitor based on pairs of presodiated manganese oxides with
the unique working mechanism of redox pseudocapacitance. Upon aging,
the holding time for voltage dropping from 1.0 to 0.4 V for the conjugated
device based on Na
x
δ-MnO2 vs Na1–x
δ-MnO2 is four times longer than that of an activated carbon (AC) vs AC
device. The successful suppression of self-discharge based on designing
device configuration is expected to be universally viable for other
capacitive materials.