No abstract

Cost‐effective electrocatalysts for the hydrogen evolution reaction (HER) spanning a wide pH range are highly desirable but still challenging for hydrogen production via electrochemical water splitting. Herein, Mo5N6‐MoS2 heterojunction nanosheets prepared on hollow carbon nanoribbons (Mo5N6‐MoS2/HCNRs) are designed as Mott–Schottky electrocatalysts for efficient pH‐universal HER. The in‐plane Mo5N6‐MoS2 Mott–Schottky heterointerface induces electron redistribution and a built‐in electric field, which effectively activates the inert MoS2 basal planes to intrinsically increase the electrocatalytic activity, improve electronic conductivity, and boost water dissociation activity. Moreover, the vertical Mo5N6‐MoS2 nanosheets provide more activated sites for the electrochemical reaction and facilitate mass/electrolyte transport, while the tightly coupled HCNRs substrate and metallic Mo5N6 provide fast electron transfer paths. Consequently, the Mo5N6‐MoS2/HCNRs electrocatalyst delivers excellent pH‐universal HER performances exemplified by ultralow overpotentials of 57, 59, and 53 mV at a current density of 10 mA cm−2 in acidic, neutral, and alkaline electrolytes with Tafel slopes of 38.4, 43.5, and 37.9 mV dec−1, respectively, which are superior to those of the reported MoS2‐based catalysts and outperform Pt in overall water splitting. This work proposes a new strategy to construct an in‐plane heterointerface on the nanoscale and provides fresh insights into the HER electrocatalytic mechanism of MoS2‐based heterostructures.

Recently, tailored synthesis of solid electrolytes meeting multiple challenges, i.e. high ionic conductivity and wide (electro)chemical stability window is of great interest. Although oxide and sulfide based solid electrolytes have...

The construction of all‐solid‐state batteries is now easier after the successful synthesis of sulfur‐based solid electrolytes with extremely high ionic conductivities. Utilizing lithium metal as the anode in these batteries requires a protective solid electrolyte layer to prevent corrosion due to the highly reactive nature of lithium. Li3N coating on lithium metal is a promising way of preventing the degradation of the electrolyte during charge and discharge. In this study, utilization of a Li3N‐coated lithium anode and Li7P3S11 solid electrolyte are reported, where a quaternary reduced graphene oxide (rGO)/S/carbon black/Li7P3S11 composite is used as cathode in the assembled cell. Our results indicate that protecting the Li metal with a Li3N coating does not affect the electrochemical characteristics of the cell and extends the cycle life of the battery. A cell assembled with a protective layer was shown to having 306 mAh g−1 capacity after 120 cycles at 160 mAh g−1 current density, whereas a cell without protective layer had a capacity of 260 mAh g−1.