Li-Ni Metal Oxides Processed with Rapid Atmospheric-Pressure-Plasma Jet for Flexible Gel-Electrolyte Li-Ion Hybrid Supercapacitors

Abstract

We use screen printing to deposit LiCl + Ni(NO3)2·6H2O pastes on a flexible carbon cloth substrate and then calcine it using a nitrogen atmospheric-pressure-plasma jet (APPJ). Through the high-temperature treatment by APPJ, pastes can be rapidly converted into Li-Ni oxides (LNOs). The LNOs on carbon cloth are then used as the electrodes of flexible gel-electrolyte Li-ion hybrid supercapacitors (Li-ion HSCs). The best areal capacity of 21.076 mC cm−2, as measured by cyclic voltammetry, is achieved by APPJ treatment at 620 °C for 480 s. To demonstrate the flexibility of the Li-ion HSCs, the Li-ion HSCs were bent at different curvatures to measure its performance. After bending test, the capacity remains >93% under bending with a curvature of up to 2 cm−1.