A Novel Flexible Hybrid Battery–Supercapacitor Based on a Self‐Assembled Vanadium‐Graphene Hydrogel
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Authors
Khazaeli, Ali
Godbille-Cardona, Gabrielle
Barz, Dominik
Date
2020-03-23
Type
journal article
Language
en
Keyword
Fast Charging , Flexible Power Sources , Hybrid Battery–Supercapacitors , Reduced Graphene Oxide , Vanadium Redox Electrolytes
Alternative Title
Abstract
A novel flexible hybrid battery–supercapacitor device is proposed consisting of high specific surface area electrodes paired with an electrolyte, which contains a redox species that can exist in more than two oxidation states. The two initially equal half‐cells of the device consist of a reduced graphene oxide hydrogel which encapsulates vanadium ions, synthesized with a single‐step method. During charge, the oxidation state of the vanadium ions changes, resulting in two half‐cells with different potentials which considerably increases the energy density. The achieved maximum capacity of more than 225 mAh g−1 is roughly eight times higher than that of comparable graphene hydrogel supercapacitors without vanadium content, but the potentiostatic charging time is only double. Operated as a supercapacitor, it retains 95% of the initial capacitance over 1000 cycles. As battery, the losses are more significant, retaining around 50% of the initial capacity. However, these losses during battery operation can be almost entirely restored by electric measures. The vanadium ion addition also improves the self‐discharge characteristics of the device. Moreover, the self‐discharge does not permanently damage the hybrid device since both half‐cells initially consist of the same vanadium graphene hydrogel and discharging resets it to initial conditions.
Description
This is the peer reviewed version of the following article: Khazaeli, A., Godbille‐Cardona, G., Barz, D. P. J., A Novel Flexible Hybrid Battery–Supercapacitor Based on a Self‐Assembled Vanadium‐Graphene Hydrogel. Adv. Funct. Mater. 2020, 1910738. https://doi.org/10.1002/adfm.201910738, which has been published in final form at https://doi.org/10.1002/adfm.201910738. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
Citation
Khazaeli, A., Godbille‐Cardona, G., Barz, D. P. J., A Novel Flexible Hybrid Battery–Supercapacitor Based on a Self‐Assembled Vanadium‐Graphene Hydrogel. Advanced Functional Materials 2020, 1910738. https://doi.org/10.1002/adfm.201910738
Publisher
Wiley