The effect of the electrodeposition temperature on the electrochemical performance of Ni(OH)₂ electrode was investigated in this report. Ni(OH)₂ was electrodeposited directly on nickel foam at different temperatures. The crystalline structure, morphology and specific surface area of the prepared Ni(OH)₂ were characterized by X-ray powder diffraction (XRD), field emission scanning electronic microscopy (FESEM) and Brunauer–Emmett–Teller (BET). Electrochemical techniques such as cyclic voltammetry (CV), chronopotentiometry, and electrochemical impedance spectra (EIS) were carried out to systematically study the electrochemical performance of various Ni(OH)₂ electrodes in 1 M KOH electrolyte. The results demonstrated that the electrodeposition temperature had obviously affected the properties of the Ni(OH)₂ . A pure α-Ni(OH)₂ phase could be observed at low temperature. When the temperature increased to 65 °C, the β-Ni(OH)₂ phase together with α-Ni(OH)₂ phase were present. Moreover, the sample synthesized at 65 °C possessed a porous honeycomb-like microstructure and the corresponding specific capacitance was up to 3357 F g⁻¹ at a charge–discharge current density of 4 A g⁻¹, which suggested its potential application as an electrode material for supercapacitors.

A three dimensional (3D) nanostructured nickel oxide (NiO) electrode was fabricated by an electrodeposition method employing nickel foam (NF) as a scaffold and used for glucose detection. Taking advantage of the synergetic effect of NF and NiO, the 3D NiO/NF electrode shows excellent performance in glucose detection.

Three dimensional manganese dioxide/Pt/nickel foam (shortened to MnPtNF) hybrid electrodes were prepared by double-pulse polarization and potentiostatic deposition technologies for supercapacitor applications. The decoration of Pt nanoparticles onto nickel foam varies the nucleation mechanism of the manganese dioxide species, inducing the formation of manganese dioxide nanosheets. Additionally, controlling the size of the Pt nanoparticles leads to modulated nanosheet architecture and electrochemical properties of the manganese dioxide electrode, as revealed by XRD, Raman spectra, SEM, TEM, cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. The nanosheet architecture of the MnPtNF electrode favors the transportation of electrons and ions, which results in the enhanced electrochemical properties. Importantly, the optimized MnPtNF electrode obtains a maximum specific capacitance of 1222 F g⁻¹ at 5 A g⁻¹ (89% of the theoretical specific capacitance of MnO₂) and 600 F g⁻¹ at 100 A g⁻¹. Moreover, the presence of Pt nanoparticles in the MnO₂ electrode effectively improves its cycling stability, which is confirmed by the increase of the specific capacitance retention from 14.7% to 90% after 600 cycles.

The phosphoric acid (PA) leakage problem has been a major constraint in the practical utilization of PA-doped polybenzimidazole for high-temperature proton exchange membranes (HT-PEMs). Increasing the retaining ability of the proton exchange membranes for free PA while decreasing the amount of PA doping seems to be a viable approach to reduce the possibility of PA leakage. In this work, the mild ester exchange reaction was introduced for the first time to prepare phosphonic acid grafted polybenzimidazoles containing pyridine (g-p-X). The phosphonic acid groups act as transport sites for proton conduction, effectively reducing the need for free PA in g-p-X membranes. Meanwhile, the pyridine immobilizes a portion of the PA through strong ionic interactions, and the membranes exhibit a high PA retention capacity. Among them, the g-p-20 membrane reaches 84.6% PA retention after the 120 h test. Thanks to the dual effects of the phosphonic acid groups and pyridine, the g-p-20 membrane shows a proton conductivity of 42 mS cm⁻¹ at 180 °C without humidification. Moreover, with only 175.3 wt% PA doping, its highest single cell power density achieves 951 mW cm⁻² (180 °C). Notably, after 120 h of steady operation at 140 °C, the voltage decay rate of the g-p-20 is only 10 μV h⁻¹. This work presents a viable concept for addressing the problem of PA leakage from HT-PEMs in long-term operation.