We demonstrate the design and fabrication of hierarchical mesoporous NiCo₂O₄@MnO₂ core–shell nanowire arrays on nickel foam via a facile hydrothermal and electrodeposition process for supercapacitor applications. In order to increase the energy density and voltage window, a high-voltage asymmetric supercapacitor based on hierarchical mesoporous NiCo₂O₄@MnO₂ core–shell nanowire arrays on nickel foam as the positive electrode and activated carbon (AC) as the negative electrode was successfully fabricated. The as-fabricated asymmetric supercapacitor device achieved a specific capacitance of 112 F g⁻¹ at a current density of 1 mA cm⁻² with a stable operational voltage of 1.5 V and a maximum energy density of 35 W h kg⁻¹. The present NiCo₂O₄@MnO₂ core–shell nanowire arrays with remarkable electrochemical properties could be considered as potential electrode materials for next generation supercapacitors in high energy density storage systems.

Copper sulphides, as a novel kind of photothermal agent for photothermal therapy (PTT) of cancer cells, have attracted increasing attention in recent years due to good photostability, synthetic simplicity, low toxicity and low cost. However, the unsatisfactory photothermal conversion efficiency of copper sulphides limits their bioapplication as PTT agents. Herein, Cu_7.2S₄ NCs with a mean size of ∼20 nm as a novel photothermal agent have been prepared by a simple thermal decomposition route. Moreover, these NCs exhibit strong near-infrared (NIR) absorption, good photostability and significant photothermal conversion efficiency up to 56.7% due to strong NIR absorption, good dispersity and suitable size. Importantly, these NCs can be very compatibly used as a 980 nm laser-driven PTT agent for the efficient PTT of cancer cells in vitro and in vivo.

Metal sulfides are commonly used in energy storage and electrocatalysts due to their redox centers and active sites. Most literature reports show that their performance decreases significantly caused by oxidation in alkaline electrolyte during electrochemical testing. Herein, S and N co‐doped graphene‐based nickel cobalt sulfide aerogels are synthesized for use as rechargeable alkaline battery electrodes and oxygen reduction reaction (ORR) catalysts. Notably, this system shows improved cyclability due to the stabilization effect of the S and N co‐doped graphene aerogel (SNGA). This reduces the rate of oxidation and the decay of electronic conductivity of the metal sulfides materials in alkaline electrolyte, i.e., the capacity decrease of CoNi₂S₄/SNGA is 4.2% for 10 000 cycles in a three‐electrode test; the current retention of 88.6% for CoS/SNGA after 12 000 s current–time chronoamperometric response in the ORR test is higher than corresponding CoS nanoparticles and CoS/non‐doped graphene aerogels. Importantly, the results here confirm that the NiCoS ternary materials behave as an electrode for rechargeable alkaline batteries rather than supercapacitors electrodes in three‐electrode test as commonly described and accepted in the literature. Furthermore, formulas to evaluate the performance of hybrid battery devices are specified.

Novel NiWO₄ and CoWO₄ nanostructures showed excellent electrochemical properties for supercapacitor electrodes, better than those previously reported for these materials.

Design and fabrication of high performance pseudocapacitors from 3D hierarchical hybrid electrodes with large areal capacitance and excellent rate capability still remains a challenge. Here, 3D hierarchical hybrid mesoporous NiCo₂O₄@Co_xNi_1−x(OH)₂ core–shell nanosheet arrays on Ni foam have been rationally designed and facilely synthesized via an electrodeposited routine for pseudocapacitor applications. Electrochemical measurements show that the NiCo₂O₄@Co_0.33Ni_0.67(OH)₂ electrode material exhibits a large areal capacitance as high as 5.71 F cm⁻² at a current density of ∼5.5 mA cm⁻², as a result of our high mass loading up to ∼5.5 mg cm⁻². Moreover, it exhibits an excellent rate capability (∼83.7% capacitance retention at 273 mA cm⁻²). Based on these excellent properties, an asymmetric supercapacitor based on 3D hierarchical hybrid mesoporous NiCo₂O₄@Co_0.33Ni_0.67(OH)₂ nanosheet arrays as the positive electrode and CMK-3 as the negative electrode was successfully fabricated. The as-fabricated device achieved the maximum areal capacitance of 887.5 mF cm⁻² (specific capacitance of 87.9 F g⁻¹) at 5 mA cm⁻² with a stable operational voltage of 1.6 V and a high energy density of 31.2 W h kg⁻¹ at a power density of 396 W kg⁻¹. Moreover, two asymmetric supercapacitors in series could power 5 mm diameter red round light-emitting diode (LED) indicators efficiently for more than 5 minutes. The present 3D hierarchical hybrid material electrode with remarkable electrochemical properties has significant potential applications in high energy density storage systems.