Multiphase interface coupling of Ni-based sulfide composites for high-current-density oxygen evolution electrocatalysis in alkaline freshwater/simulated seawater/seawater.

Constructing highly efficient electrocatalysts is vital to enhance oxygen evolution reaction (OER) performance at industrially relevant current densities. Herein, three-phase coupled Ni3S2/r-NiS/h-NiS composites are grown in situ on Ni foam (NNSN/NF) via a one-step solvothermal approach. The as-prepared composites need overpotentials of only 377 mV, 451 mV and 476 mV at 1000 mA cm-2 for the OER in alkaline freshwater, simulated seawater and seawater, respectively. In addition, the optimized catalyst exhibited long-term durability at 300 mA cm-2. Our work clarifies designing and preparing cost-effective Ni-based sulfide electrocatalysts for the OER in alkaline freshwater/simulated seawater/seawater under industrially relevant current densities.

One-step electrodeposited Ni3S2/Co9S8/NiS composite on Ni foam as high-performance electrode for supercapacitors.

Transition metal sulfides (TMSs) are considered as one of the promising electrode materials due to their fascinating redox reversibility and electronic conductivity. However, volume expansion during the charge/discharge process impedes their practical applications. The reasonable design of TMS electrode materials with unique morphology can improve the energy storage performance. Herein, we prepared the Ni3S2/Co9S8/NiS composite that is in situ grown on Ni foam (NF) via a one-step electrodeposition process. The optimized Ni3S2/Co9S8/NiS-7 shows a superhigh specific capacity of 2785.3 F g-1 at 1 A g-1 and remarkable rate capability. Furthermore, the as-assembled device displays a high energy density of 40.1 W h kg-1 at a power density of 799.3 W kg-1 and a satisfactory stability of 96.6% retention after 5000 cycles. This work provides a facile way to fabricate new TMS electrode materials for high-performance supercapacitors.

CuCoNi-S anchored CoMoO4/MoO3 forming core-shell structure for high-performance asymmetric supercapacitors.

Although the preparation of transition metal sulfides/oxides electrodes has been relatively perfected, it is still challenging to fabricate multi-component transition metal sulfides/oxides core-shell structure electrodes with excellent electrochemical performance. Herein, CoMoO4/MoO3@CuCoNi-S grown on nickel foam (NF) is first synthesized via facile hydrothermal and electrodeposition methods. The CoMoO4/MoO3@CuCoNi-S electrode presents an exceptional specific capacitance (2600.0 F g-1 at 1 A g-1) and 68.3% of its initial capacitance at 10 A g-1. Moreover, a CoMoO4/MoO3@CuCoNi-S//active carbon (AC) device is assembled for determining its electrochemical application. It reveals a high energy density of 42.1 W h kg-1 at a power density of 800.2 W kg-1, an extended voltage window of 1.6 V and excellent stability with 96.9% retention after 5000 cycles at 2 A g-1. This work offers a reference case for the development of multi-component transition metal sulfides/oxides core-shell structure composites for energy storage.

Multi-interface MoS2/Ni3S4/Mo2S3 composite as an efficient electrocatalyst for hydrogen evolution reaction over a wide pH range.

The exploitation of cost-efficiently electrocatalysts for hydrogen evolution reaction (HER) over a wide pH range remains a challenge. Herein, we prepared a novel multi-interface MoS2/Ni3S4/Mo2S3 composite on carbon cloth (CC) that acts as an efficient electrocatalyst over a wide pH range through a facile one-pot strategy, where (NH4)4[NiH6Mo6O24]·5H2O (abbreviated to NiMo6) as a bimetallic precursor and Ni(NO3)2·6H2O as one of the raw materials and salt are used together with thiourea (TU) for converting them into the MoS2/Ni3S4/Mo2S3 load on CC (abbreviated as MoS2/Ni3S4/Mo2S3/CC). MoS2/Ni3S4/Mo2S3/CC-24 h shows a distinguished electrocatalytic performance towards HER with long-term stability in acid and alkaline media. It presents low overpotentials of 38 mV and 51 mV in 0.5 M H2SO4 and 1.0 M KOH at 10 mA cm-2, respectively. This work can deliver a new idea to fabricate cost-efficient and long-term durability HER electrocatalysts over a broad pH range.

Controllable Synthesis of Peapod-like Sb@C and Corn-like C@Sb Nanotubes for Sodium Storage.

Antimony (Sb) is regarded as an attractive anode material for sodium-ion batteries (SIBs) due to its high theoretical capacity of 660 mAh g-1. Combining Sb with carbonaceous materials has been considered as an effective way to resolve the serious volume expansion issues. Sb/C composites mainly consist of two types, that is, Sb confined inside a carbon matrix and Sb deposited on the surface of a carbon matrix, and both have shown superior sodium storage performance. However, which structure is more beneficial for achieving high electrochemical performance is still unclear. In this work, peapod-like Sb@C and corn-like C@Sb nanotubes are synthesized via a nanoconfined galvanic replacement reaction and used as model materials for sodium storage to explore the above issue. When evaluated as anode materials for SIBs, the peapod-like Sb@C shows a higher rate capability and a significantly better long-term cycling stability compared to those of the corn-like C@Sb. Electrochemical analysis reveals that the peapod-like Sb@C exhibits faster Na+ and electron transport kinetics and higher proportions of surface capacitive contributions. These results demonstrate the structural superiority of the nanoconfined structure and provide valuable information for the rational design and construction of Sb-based anode materials for high-performance electrochemical energy storage.

Tetra-imidazolium hexa-µ(4)-oxido-dodeca-µ(2)-oxido-dodeca-oxidohexa-arsenate(III)hexa-molybdenum(VI)cuprate(II).

The title compound, (C(3)H(5)N(2))(4)[As(6)CuMo(6)O(30)], is made up of a centrosymmetric anionic cluster and four imidazolium cations. In the cluster, the central Cu(II) atom is six-coordinated and lies on an inversion center. Adjacent clusters are linked via N-H⋯O hydrogen bonds between the imidazole cations and polyoxidoanions into a three-dimensional supra-molecular architecture.