The development of highly efficient bifunctional electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is crucial for improving the efficiency of overall water splitting, but still remains challenging issue. Herein, 3D self-supported Fe-doped Ni 2 P nanosheet arrays are synthesized on Ni foam by hydrothermal method followed by in situ phosphorization, which serve as bifunctional electrocatalysts for overall water splitting. The as-synthesized (Ni 0.33 Fe 0.67 ) 2 P with moderate Fe doping shows an outstanding OER performance, which only requires an overpotential of ≈230 mV to reach 50 mA cm −2 and is more efficient than the other Fe incorporated Ni 2 P electrodes. In addition, the (Ni 0.33 Fe 0.67 ) 2 P exhibits excellent activity toward HER with a small overpotential of ≈214 mV to reach 50 mA cm −2 . Furthermore, an alkaline electrolyzer is measured using (Ni 0.33 Fe 0.67 ) 2 P electrodes as cathode and anode, respectively, which requires cell voltage of 1.49 V to reach 10 mA cm −2 as well as shows excellent stability with good nanoarray construction. Such good performance is attributed to the high intrinsic activity and superaerophobic surface property.Herein, we fabricated self-supported Fe-doped Ni 2 P nanosheet arrays on the Ni foam by simple hydrothermal method and in situ phosphorization. The performance of Fe-doped Ni 2 P nanosheet arrays as bifunctional catalysts toward overall water splitting depends strongly on the Fe doping ratio in the Ni 2 P. The optimized Fe doping of Ni 2 P [(Ni 0.33 Fe 0.67 ) 2 P] showed excellent HER activity with an overpotential of ≈214 mV to reach 50 mA cm −2 and superior OER performance with a lower overpotential of ≈230 mV to reach 50 mA cm −2 , outperforming the commercial Ir/C. As expected, the electrolyzer using Ni 2 P nanosheet arrays with 31.7% Fe doping as both anode and cathode electrodes for catalyzing overall water splitting exhibited the best performance, obtaining a current density of 10 mA cm −2 at 1.49 V, better than the integration of commercial Pt/C and Ir/C electrodes.

Terminal –OH group in PEO-based solid polymer electrolytes is the limiting factor of the electrochemical stability window, replacing it with more stable groups can accelerate the development of high-voltage solid-state batteries.

The growing demand for sustainable energy storage devices requires rechargeable lithium‐ion batteries (LIBs) with higher specific capacity and stricter safety standards. Ni‐rich layered transition metal oxides outperform other cathode materials and have attracted much attention in both academia and industry. Lithium‐ion batteries composed of Ni‐rich layered cathodes and graphite anodes (or Li‐metal anodes) are suitable to meet the energy requirements of the next generation of rechargeable batteries. However, the instability of Ni‐rich cathodes poses serious challenges to large‐scale commercialization. This paper reviews various degradation processes occurring at the cathode, anode, and electrolyte in Ni‐rich cathode‐based LIBs. It highlights the recent achievements in developing new stabilization strategies for the various battery components in future Ni‐rich cathode‐based LIBs.

Exploring bifunctional catalysts for the hydrogen and oxygen evolution reactions (HER and OER) with high efficiency, low cost, and easy integration is extremely crucial for future renewable energy systems. Herein, ternary NiCoP nanosheet arrays (NSAs) were fabricated on 3D Ni foam by a facile hydrothermal method followed by phosphorization. These arrays serve as bifunctional alkaline catalysts, exhibiting excellent electrocatalytic performance and good working stability for both the HER and OER. The overpotentials of the NiCoP NSA electrode required to drive a current density of 50 mA/cm 2 for the HER and OER are as low as 133 and 308 mV, respectively, which is ascribed to excellent intrinsic electrocatalytic activity, fast electron transport, and a unique superaerophobic structure. When NiCoP was integrated as both anodic and cathodic material, the electrolyzer required a potential as low as ~1.77 V to drive a current density of 50 mA/cm 2 for overall water splitting, which is much smaller than a reported electrolyzer using the same kind of phosphide-based material and is even better than the combination of Pt/C and Ir/C, the best known noble metal-based electrodes. Combining satisfactory working stability and high activity, this NiCoP electrode paves the way for exploring overall water splitting catalysts.