Abstract
The recent advancement in flexible/bendable displays such as phones, smart bands, laptops, and televisions demands flexible energy storage devices. Heteroatom-doped graphene electrodes are promising candidates for flexible energy-storage applications because of its dual nature of electrochemical double-layer capacitance and pseudocapacitance. The low energy density of supercapacitors limits their potential use and attempts are in progress to overcome this issue. Redox-additive electrolytes are presumed to be one of the elite tactics to augment the energy density of the supercapacitor device. Here, the sodium molybdate (Na2MoO4)-incorporated polymer gel electrolyte has been demonstrated to enhance the energy density of a flexible supercapacitor. The supercapacitor electrode with Na2MoO4/H2SO4 (714 F/g) acquired ∼2.4-fold greater specific capacitance than with H2SO4 (300 F/g) in a three-electrode configuration. Moreover, the energy density of symmetric supercapacitor with Na2MoO4/H2SO4 (23 Wh/kg) is ∼2-fold higher compared with H2SO4 electrolyte (13 Wh/kg). The fabricated flexible supercapacitor device with sodium molybdate/ poly(vinyl alcohol)/sulfuric acid (Na2MoO4/PVA/H2SO4) gel electrolyte showed 3.4-fold higher energy density (E = 24 Wh/kg) compared to a device with PVA/H2SO4 gel electrolyte (E = 7 Wh/kg). The increase in energy density has been observed after the incorporation of Na2MoO4, which is due to the faradaic reaction between the MoO24− ions in the redox-additive and H+ ions in the H2SO4 electrolyte.
Original language | English |
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Pages (from-to) | 11368-11377 |
Number of pages | 10 |
Journal | ACS Applied Energy Materials |
Volume | 3 |
Issue number | 11 |
DOIs | |
State | Published - 23 Nov 2020 |
Externally published | Yes |
Keywords
- Flexible supercapacitor
- Heteroatom doped graphene
- High energy density
- Redox additives
- Sodium molybdate
ASJC Scopus subject areas
- Chemical Engineering (miscellaneous)
- Energy Engineering and Power Technology
- Electrochemistry
- Materials Chemistry
- Electrical and Electronic Engineering