N-doped MoS2@indium tin oxide (ITO) core–shell nanowires for high-performance ammonium ion micro-supercapacitor

Abstract

Ammonium (NH4+) ion aqueous supercapacitors have gained significant attention due to their notable cost-effectiveness, safety profile, and environmental benefits. Despite this, the optimization of the capacitive performance of electrode materials for NH4+ ion storage remains inadequate. To tackle these challenges, we present a composite electrode depend upon molybdenum disulfide (MoS2) and indium tin oxide nanowires (MoS2@ITO NWs) as the primary host for (NH4+) ions. Additionally, we introduce a straightforward radio frequency nitrogen (N) plasma technique to incorporate nitrogen doping into the MoS2 film, thereby enhancing its performance. The introduction of N plasma doping into two-dimensional MoS2 results in an expansion of the interlayer distance and an improvement in electronic conductivity. This, in turn, facilitates the facile and highly reversible insertion and extraction of NH4+ ions during cycling. Consequently, the N plasma doping significantly enhances the device areal capacitance of MoS2@ITO NWs, increasing it from 78.6 to 161.8 mF cm−2 at 1 mA cm−2, with an exceptional capacity retention (>89.2% after 10 000 cycles) and superior rate capability up to 10 mA cm−2. The integration N of atoms within the straightforward hierarchical core–shell design strategy exhibits promising prospects for bolstering the performance of metal sulfide electrodes and other high-capacity electrode materials aimed at energy storage applications.