High-performance ZnCo2O4 microsheets as an anode for lithium-ion batteries

Enhanced Energy Storage Properties and DFT Investigation of a Zn-Co-Mo Heterojunction Rich in Oxygen Vacancies with Dual Electron Transport Pathways

Petal-like heterojunction materials ZnCo2O4/CoMoO4 with abundant oxygen vacancies are prepared on nickel foam (NF) using modified ionic hybrid thermal calcination technology. Nanoscale ion intermixing between Zn and Mo ions induces oxygen vacancies in the annealing process, thus creating additional electrochemical active sites and enhancing the electrical conductivity. The ZnCo2O4/CoMoO4 conductive network skeleton forms the primary transport pathway for electrons, while the internal electric field of the heterojunction serves as the secondary pathway. ZnCo2O4/CoMoO4 exhibits excellent rate performance and high capacity attributable to its unique double electron transport mode and the effect of oxygen vacancies. The initial discharge capacity at a current of 0.1 A g-1 is approximately 1774 mAh g-1, and the reversible capacity remains at 1100 mAh g-1 after 200 cycles. After a high current of 1 A g-1, the reversible capacity is observed to remain at approximately 1240 mAh g-1. The electronic structure, crystal structure, and work function of the heterojunction interface model are then analyzed by density functional theory (DFT). The analysis results indicate that the charge at the ZnCo2O4/CoMoO4 interface is unevenly distributed, which leads to an enhanced degree of electrochemical reaction. The presence of an internal electric field improves the transport efficiency of the carriers. Experimental and theoretical calculations demonstrate that the ZnCo2O4/CoMoO4 anode material designed in this work provides a reference for fabricating transition metal oxide-based lithium-ion batteries.

Recent Advances in Rechargeable Metal-CO2 Batteries with Nonaqueous Electrolytes

This review article discusses the recent advances in rechargeable metal-CO2 batteries (MCBs), which include the Li, Na, K, Mg, and Al-based rechargeable CO2 batteries, mainly with nonaqueous electrolytes. MCBs capture CO2 during discharge by the CO2 reduction reaction and release it during charging by the CO2 evolution reaction. MCBs are recognized as one of the most sophisticated artificial modes for CO2 fixation by electrical energy generation. However, extensive research and substantial developments are required before MCBs appear as reliable, sustainable, and safe energy storage systems. The rechargeable MCBs suffer from the hindrances like huge charging-discharging overpotential and poor cyclability due to the incomplete decomposition and piling of the insulating and chemically stable compounds, mainly carbonates. Efficient cathode catalysts and a suitable architectural design of the cathode catalysts are essential to address this issue. Besides, electrolytes also play a vital role in safety, ionic transportation, stable solid-electrolyte interphase formation, gas dissolution, leakage, corrosion, operational voltage window, etc. The highly electrochemically active metals like Li, Na, and K anodes severely suffer from parasitic reactions and dendrite formation. Recent research works on the aforementioned secondary MCBs have been categorically reviewed here, portraying the latest findings on the key aspects governing secondary MCB performances.

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.