Nickel‐Based Sulfide Materials for Batteries

Revealing the unique process of alloying reaction in Ni-Co-Sb/C nanosphere anode for high-performance lithium storage

The strategy of "template sacrifice method" was proposed to synthesize well-defined NiSb/CoSb nanoparticles embedded in carbon nanosphere (Ni-Co-Sb/C, ~560 nm) by calcination treatment of the Ni-Co-MOF (metal-organic framework) precursor. Due to the structural controllability of MOF precursor and Ni/Co bimetallic synergy, the fabricated Ni-Co-Sb/C demonstrates a high surface area (88 m² g^-1) and superior ion conductivity, thus an excellent electrochemical performance as has been achieved as lithium ion battery (LIB) anode. A reversible discharge specific capacity as high as 495.1 mAh g^-1 has been stably delivered after 1000 cycles at a high current density of 1.0 A g^-1. In addition, the charge transfer impedance of Ni-Co-Sb/C electrode is as low as 67.6 Ω in the 30th cycle at 0.1 A g^-1 and the pseudocapacitive contribution is as high as 73.8% at 0.5 mV s^-1. The alloying mechanism of Ni-Co-Sb/C has been verified by in-situ X-ray diffraction (XRD), which enables a high lithium storage capacity. Moreover, the full-cell assembled with LiCoO₂ as cathode exhibits a steady discharge specific capacity of 354.0 mAh g^-1 at 0.1 A g^-1 even after 100 cycles. Our work provides an effective method for the application and high-capacity Sb-based material in energy storage fields, and this material is expected as a promising candidate for a novel anode material in LIBs.

Enhanced Electrocatalytic Activity of Stainless Steel Substrate by Nickel Sulfides for Efficient Hydrogen Evolution

Water splitting is one of the efficient ways to produce hydrogen with zero carbon dioxide emission. Thus far, Pt has been regarded as a highly reactive catalyst for the hydrogen evolution reaction (HER); however, the high cost and rarity of Pt significantly hinder its commercial use. Herein, we successfully developed an HER catalyst composed of NiSx (x = 1 or 2) on stainless steel (NiSx/SUS) using electrodeposition and sulfurization techniques. Notably, the electrochemical active surface area(ECSA) of NiSx/SUS was improved more than two orders of magnitude, resulting in a considerable improvement in the electrochemical charge transfer and HER activity in comparison with stainless steel (SUS). The long-term HER examination by linear scan voltammetry (LSV) confirmed that NiSx/SUS was stable up to 2000 cycles.

Core–shell-type ZIF-8@ZIF-67@POM hybrids as efficient electrocatalysts for the oxygen evolution reaction

ZIF-8@ZIF-67@POM hybrids were synthesized using a simple coprecipitation method, and they exhibit remarkable performance in OER, with the synergistic effect between POM and ZIF species, their regular architecture and their high surface area.