Ultrafast Fabrication of H2SO4, LiCl, and Li2SO4 Gel Electrolyte Supercapacitors with Reduced Graphene Oxide (rGO)-LiMnOx Electrodes Processed Using Atmospheric-Pressure Plasma Jet

Pei-Ling Lan; I-Chih Ni; Chih-I Wu; Cheng-Che Hsu; I-Chun Cheng; Jian-Zhang Chen

doi:10.3390/mi14091701

Ultrafast Fabrication of H₂SO₄, LiCl, and Li₂SO₄ Gel Electrolyte Supercapacitors with Reduced Graphene Oxide (rGO)-LiMnO_x Electrodes Processed Using Atmospheric-Pressure Plasma Jet

Micromachines (Basel). 2023 Aug 30;14(9):1701. doi: 10.3390/mi14091701.

Authors

Pei-Ling Lan^{1

2}, I-Chih Ni³, Chih-I Wu^{3

4}, Cheng-Che Hsu⁵, I-Chun Cheng³, Jian-Zhang Chen^{1

2

4}

Affiliations

¹ Graduate Institute of Applied Mechanics, National Taiwan University, Taipei City 10617, Taiwan.
² Advanced Research Center for Green Materials Science and Technology, National Taiwan University, Taipei City 10617, Taiwan.
³ Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei City 10617, Taiwan.
⁴ Graduate School of Advanced Technology, National Taiwan University, Taipei City 10617, Taiwan.
⁵ Department of Chemical Engineering, National Taiwan University, Taipei City 10617, Taiwan.

Abstract

Pastes containing reduced graphene oxide (rGO) and LiCl-Mn(NO₃)₂·4H₂O are screen-printed on a carbon cloth substrate and then calcined using a nitrogen atmospheric-pressure plasma jet (APPJ) for conversion into rGO-LiMnO_x nanocomposites. The APPJ processing time is within 300 s. RGO-LiMnO_x on carbon cloth is used to sandwich H₂SO₄, LiCl, or Li₂SO₄ gel electrolytes to form hybrid supercapacitors (HSCs). The areal capacitance, energy density, and cycling stability of the HSCs are evaluated using electrochemical measurement. The HSC utilizing the Li₂SO₄ gel electrolyte exhibits enhanced electrode-electrolyte interface reactions and increased effective surface area due to its high pseudocapacitance (PC) ratio and lithium ion migration rate. As a result, it demonstrates the highest areal capacitance and energy density. The coupling of charges generated by embedded lithium ions with the electric double-layer capacitance (EDLC) further contributed to the significant overall capacitance enhancement. Conversely, the HSC with the H₂SO₄ gel electrolyte exhibits better cycling stability. Our findings shed light on the interplay between gel electrolytes and electrode materials, offering insights into the design and optimization of high-performance HSCs.

Keywords: atmospheric-pressure plasma (APP); flexible electronics; reduced graphene oxide (rGO); supercapacitor (SC).

Abstract

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