Tuning growth of MoS2 nanowires over NiTiCu nanostructured array for flexible supercapacitive electrodes with enhanced Li-ion storage

Rationally engineered three-dimensional (3D) clusters of MoS2 nanowires vertically anchored over a nanostructured NiTiCu shape memory alloy are fabricated using magnetron sputtering for flexible thin film supercapacitive electrodes. The heterostructure MoS2/NiTiCu deposited directly over flexible stainless steel (SS) offers remarkable electrochemical performance along with excellent mechanical stability, arising synergistically from the large specific surface of MoS2 nanowires and a high mechanical strength of NiTiCu@SS. The electrochemical studies in sulfate electrolytes (Li2SO4 and Na2SO4) manifest dominant charge transport efficiency of Li+ into the easily accessible electroactive sites of MoS2. The electrode delivers a superior gravimetric capacitance (379.25 F/g at 0.78 A/g) in addition to outstanding cycling stability (95.9% over 5000 cycles), suggesting high Li+ conductivity, low equivalent series resistance, and good substrate adhesion. Furthermore, the Power law and Dunn's approach reveal that charge storage into the highly porous MoS2 networks occurs mainly through the pseudocapacitive mechanism in Li2SO4 and capacitive processes in Na2SO4. Practically flexing the working electrode over 1000 bending cycles degrades the capacitance by only 17.17%, achieving highly desirable mechanical stability. Significantly, a superior power density of 12.54 kW/kg, while simultaneously achieving a high energy density of 52.67 Wh/kg, presents the electrode's immense potential for high-performance supercapacitor devices in flexible electronics.

Automated summary

By fabricating a heterostructure of MoS2/NiTiCu directly on flexible stainless steel, a superior electrode with remarkable electrochemical performance and excellent mechanical stability was achieved. The electrode exhibits superior gravimetric capacitance, outstanding cycling stability, and can withstand over 1000 bending cycles while maintaining high performance.