Ni, S co-doped Cu dendrites decorated with core-shell architecture assisted by MOF and Fe0.92Co0.08S nanoflakes on nanocellulose/graphene fibers for fabrication of flexible wire-typed micro-supercapacitor

Abstract

One-dimensional micro-supercapacitor (1D micro-SC) have been regarded as an efficient energy storage system to fulfill the ever-growing need of the miniaturized electronics. Designing multi-dimensional nanoarchitectures on fibrous microelectrodes is an effective strategy to build high-performance 1D micro-SC. In this work, Ni,S-doped Cu was firstly prepared on Cu wire as micro-sized 1D current collector using Cu electrodeposition through H2 bubble template and then co-doped by nickel and sulfur. Benefiting from high electricity/thermal conductivity of Cu, high electroactive sites of Ni and S, as well as 3D porous architecture, deposited Ni,S-doped Cu provided a platform for growing active substances. Afterwards, cobalt carbonate hydroxide (CoCH) pine-like nanoneedles integrated ZIF-67 polyhedrons were synthesized on foam-like skeleton and then converted into NiMoCo- layered triple hydroxide (LTH)/Ni,S-doped Cu shish-kebab type nanoarrays by a hydrothermal method. In the end, Ni2Mo3N-CoN/Ni,S-doped Cu was prepared by the nitridation process. By taking advantages of potent interaction and synergy between components, well-organized hybrid nanoarchitecture consisting of dodecahedrons penetrated on needle-like arrays in a 3D framework produces rich redox properties, rapid ion/electron conveying dynamics and high electroactivity. In comparison to LTH obtained from electrodeposition method (without ZIF-67 precursor) as well as derived from leaf-like ZIF-Co, this modified microfiber exhibited high charge storage capacity of 1.5 mAh cm-2 (149.9 mAh cm-3, 0.187 mAh cm-1) at 4 mA cm-2 and possesses excellent durability of 98.4% after 5000 cycles. Additionally, FeCoS nanoflakes was electrodeposited on carbon fiber coated with rGO- nanocellulose hydrogel (GNCH) and employed as negative 1D microelectrode, which delivered high specific capacitance of 1223 mF cm-2 (83 F cm-3, 232.4 mF cm-1) at 4 mA cm-2 with superior cyclic lifespan. Ultimately, the assembled 1D flexible micro-device (Ni2Mo3N-CoN/Ni,S-doped Cu@CW//FeCoS/GNCH@CF) yielded energy density of 7.2 mWh cm-3 at the power density of 294 mW cm-3 and outstanding cycling stability in PVA/KOH electrolyte, furthermore, still preserves the capacitive performance under various bending states. The research highlights that assembled 1D micro-SC have high potency for next-generation portable/wearable energy-supply microelectronics.