Yifei Pei

The urea electro-oxidation reaction (UOR) is emerging as a new energy conversion technology and a promising method for alleviating water eutrophication problems. However, a rationally designed structure of the electrode materials is urgently required to achieve high UOR performance. Herein, P-doped MOF-derived Co₃O₄ nanowire arrays grown on nickel foam (P-Co₃O₄/NF) are successfully synthesized via the growth of Co-MOF and subsequent calcination followed by phosphorization treatment. Owing to the optimized electronic structure, the as-prepared P-Co₃O₄/NF composite exhibits much higher UOR electrocatalytic performance than the undoped Co₃O₄/NF sample. Beyond this, the meticulous structure of the one-dimensional nanowire arrays and the three-dimensional skeleton structure of nickel foam contribute to the enhanced electrocatalytic activity and stability toward UOR. As a result, the P-Co₃O₄/NF composite displays a low overpotential of 1.419 V vs. RHE at 50 mA cm⁻², a small Tafel slope of 82 mV dec⁻¹, as well as favorable long-term stability over 65,000 s in 1.0 M KOH with 1.0 M urea. This work opens a new avenue in designing non-precious electrocatalysts for high-performance urea electro-oxidation reactions.

Zinc-based batteries (ZBBs) have proven to be tremendously plausible for large-scale electrochemical energy storage applications due to their merits of desirable safety, low-cost, and low environmental impact. Nevertheless, the zinc metal anodes in ZBBs still suffer from many issues, including dendrite growth, hydrogen evolution reactions (HERs), corrosion, passivation, and other types of undesirable side reactions, which severely hinder practical application. The modification of Cu-based current collectors (CCs) has proven to be an efficient method to regulate zinc deposition and prevent dendritic growth, thereby improving the Coulombic efficiency (CE) and lifespan of batteries (e.g., up to 99.977% of CE over 6900 cycles after modification), which is an emerging research topic in recent years. In this review, we provide a systematic overview of the modification of copper-based CCs and their application in zinc metal anodes. The relationships between their modification strategies, nano-micro-structures, and electrochemical performance are systematically reviewed. Ultimately, their promising prospects for future development are also proposed. We hope that this review could contribute to the design of copper-based CCs for zinc-based batteries and facilitate their practical application.

Alkali metals (Li, Na, and K) are deemed as the ideal anode materials for next-generation high-energy-density batteries because of their high theoretical specific capacity and low redox potentials. However, alkali metal anodes (AMAs) still face some challenges hindering their further applications, including uncontrollable dendrite growth and unstable solid electrolyte interphase during cycling, resulting in low Coulombic efficiency and inferior cycling performance. In this regard, designing 3D current collectors as hosts for AMAs is one of the most effective ways to address the above-mentioned problems, because their sufficient space could accommodate AMAs’ volume expansion, and their high specific surface area could lower the local current density, leading to the uniform deposition of alkali metals. Herein, we review recent progress on the application of 3D Cu-based current collectors in stable and dendrite-free AMAs. The most widely used modification methods of 3D Cu-based current collectors are summarized. Furthermore, the relationships among methods of modification, structure and composition, and the electrochemical properties of AMAs using Cu-based current collectors, are systematically discussed. Finally, the challenges and prospects for future study and applications of Cu-based current collectors in high-performance alkali metal batteries are proposed.

Aqueous zinc ion batteries (AZIBs) are considered as one of the most promising energy storage technologies due to their advantages of being low in cost, high in safety, and their environmental friendliness. However, dendrite growth and parasitic side reactions on the zinc metal anode during cycling lead to a low coulombic efficiency and an unsatisfactory lifespan, which seriously hinders the further development of AZIBs. In this regard, metal–organic frameworks (MOFs) are deemed as suitable surface modification materials for the Zn anode to deal with the abovementioned problems because of their characteristics of a large specific surface area, high porosity, and excellent tunability. Considering the rapidly growing research enthusiasm for this topic in recent years, herein, we summarize the recent advances in the design, fabrication, and application of MOFs and their derivatives in the surface modification of the zinc metal anode. The relationships between nano/microstructures, synthetic methods of MOF-based materials, and the enhanced electrochemical performance of the zinc metal anode via MOF surface modification are systematically summarized and discussed. Finally, the existing problems and future development of this area are proposed.

Aqueous Zn-ion batteries (AZIBs) are one of the most promising large-scale energy storage devices due to the excellent characteristics of zinc metal anode, including high theoretical capacity, high safety and low cost. Nevertheless, the large-scale applications of AZIBs are mainly limited by uncontrollable Zn deposition and notorious Zn dendritic growth, resulting in low plating/stripping coulombic efficiency and unsatisfactory cyclic stability. To address these issues, herein, a carbon foam (CF) was fabricated via melamine-foam carbonization as a scaffold for a dendrite-free and stable Zn anode. Results showed that the abundant zincophilicity functional groups and conductive three-dimensional network of this carbon foam could effectively regulate Zn deposition and alleviate the Zn anode’s volume expansion during cycling. Consequently, the symmetric cell with CF@Zn electrode exhibited lower voltage hysteresis (32.4 mV) and longer cycling performance (750 h) than the pure Zn symmetric cell at 1 mA cm⁻² and 1 mAh cm⁻². Furthermore, the full battery coupling CF@Zn anode with MnO₂ cathode can exhibit a higher initial capacity and better cyclic performance than the one with the bare Zn anode. This work brings a new idea for the design of three-dimensional (3D) current collectors for stable zinc metal anode toward high-performance AZIBs.