Recent Advances of ZnCo2 O4 -based Anode Materials for Li-ion Batteries

ZnCo₂ O₄ has been attracted wide research attention as a promising anode material for lithium-ion batteries (LIBs) in recent years based on its high theoretical specific capacity, low toxicity as well as stable chemical properties. However, the further large-scale application of pristine ZnCo₂ O₄ anode have been impeded because of its undesirable Li⁺ ion conductivity, low electronic conductivity, and finite stability of electrolytes at high potentials. Recently, optimizing the micro/nano structure, modification with carbonaceous materials, incorporation with metal oxides and constructing a binder-free structure on conductive substrate for ZnCo₂ O₄ -based materials have been verified as promising effective routes for solving the above problems. In this review, the recent advances in underlying reaction mechanisms, synthetic methods and strategies for improving the performance of ZnCo₂ O₄ anodes are comprehensively summarized. The factors affecting the electrochemical properties of ZnCo₂ O₄ -based materials are mainly discussed, and paths to promote the specific capacity and cyclic stability are proposed. Finally, several insights into the future developments, challenges, and prospects of ZnCo₂ O₄ -based anode materials of LIBs are proposed.

Growth of large-scale MoS2 nanosheets on double layered ZnCo2O4 for real-time in situ H2S monitoring in live cells

There is an urgent need to develop in situ sensors that monitor the continued release of H2S from biological systems to understand H2S-related pathology and pharmacology. For this purpose, we have developed a molybdenum disulfide supported double-layered zinc cobaltite modified carbon cloth electrode (MoS2-ZnCo2O4-ZnCo2O4) based electrocatalytic sensor. The results of our study suggest that the MoS2-ZnCo2O4-ZnCo2O4 electrode has excellent electrocatalytic ability to oxidize H2S at physiological pH, in a minimized overpotential (+0.20 vs. Ag/AgCl) with an amplified current signal. MoS2 grown on double-layered ZnCo2O4 showed relatively better surface properties and electrochemical properties than MoS2 grown on single-layered ZnCo2O4. The sensor delivered excellent analytical parameters, such as low detection limit (5 nM), wide linear range (10 nM-1000 μM), appreciable stability (94.3%) and high selectivity (2.5-fold). The practicality of the method was tested in several major biological fluids. The electrode monitors the dynamics of bacterial H2S in real-time for up to 5 h with good cell viability. Our research shows that MoS2-ZnCo2O4-ZnCo2O4/carbon cloth is a robust and sensitive electrode to understand how bacteria seek to adjust their defense strategies under exogenously induced stress conditions.

Synthesis of interconnected mesoporous ZnCo2O4 nanosheets on a 3D graphene foam as a binder-free anode for high-performance Li-ion batteries

Interconnected mesoporous sheet-like ZnCo2O4 nanomaterials directly grown on a three-dimensional (3D) graphene film (GF) coated on Ni foam (NF) have been successfully synthesized via an effective chemical vapor deposition (CVD) method combined with a subsequent hydrothermal route. When the ZnCo2O4@3DGF@NF composite material with a high surface area of 46.06 m2 g-1 is evaluated as a binder-free anode material for lithium ion batteries, it exhibits a superior electrochemical performance with a high discharge capacity (1223 mA h g-1 at a current density of 500 mA g-1 after 240 cycles), and an excellent reversibility (coulombic efficiency of 97-99%). Such an outstanding electrochemical performance may be attributed to its unique mesoporous sheet-like nanostructure with a 3DGF supporting, which can facilitate the electrolyte penetration and accelerate the ion/electron transport, as well as buffer the volume variation during charge/discharge processes.