An Asymmetric Supercapacitor-Diode (CAPode) for Unidirectional Energy Storage.

ABSTRACT: A new asymmetric capacitor concept is proposed providing high energy storage capacity for only one charging direction. Size-selective microporous carbons (w<0.9?nm) with narrow pore size distribution are demonstrated to exclusively electrosorb small anions (BF₄ ^- ) but size-exclude larger cations (TBA⁺ or TPA⁺ ), while the counter electrode, an ordered mesoporous carbon (w>2?nm), gives access to both ions. This architecture exclusively charges in one direction with high rectification ratios (RR=12), representing a novel capacitive analogue of semiconductor-based diodes ("CAPode"). By precise pore size control of microporous carbons (0.6?nm, 0.8?nm and 1.0?nm) combined with an ordered mesoporous counter electrode (CMK-3, 4.8?nm) electrolyte cation sieving and unidirectional charging is demonstrated by analyzing the device charge-discharge response and monitoring individual electrodes of the device via in?situ NMR spectroscopy.

SUBMITTER: Zhang E 

PROVIDER: S-EPMC6772186 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature