Advances of Nanomaterials for High-Efficiency Zn Metal Anodes in Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries (AZIBs) have emerged as one of the most promising candidates for next-generation energy storage devices due to their outstanding safety, cost-effectiveness, and environmental friendliness. However, the practical application of zinc metal anodes (ZMAs) faces significant challenges, such as dendrite growth, hydrogen evolution reaction, corrosion, and passivation. Fortunately, the rapid rise of nanomaterials has inspired solutions for addressing these issues associated with ZMAs. Nanomaterials with unique structural features and multifunctionality can be employed to modify ZMAs, effectively enhancing their interfacial stability and cycling reversibility. Herein, an overview of the failure mechanisms of ZMAs is presented, and the latest research progress of nanomaterials in protecting ZMAs is comprehensively summarized, including electrode structures, interfacial layers, electrolytes, and separators. Finally, a brief summary and optimistic perspective are given on the development of nanomaterials for ZMAs. This review provides a valuable reference for the rational design of efficient ZMAs and the promotion of large-scale application of AZIBs.

A Zero-Strain Insertion Cathode Material for Room-Temperature Fluoride-Ion Batteries.

A fluoride-ion battery (FIB) is a novel type of energy storage system that has a higher volumetric energy density and low cost. However, the high working temperature (>150 °C) and unsatisfactory cycling performance of cathode materials are not favorable for their practical application. Herein, fluoride ion-intercalated CoFe layered double hydroxide (LDH) (CoFe-F LDH) was prepared by a facile co-precipitation approach combined with ion-exchange. The CoFe-F LDH shows a reversible capacity of ∼50 mAh g-1 after 100 cycles at room temperature. Although there is still a big gap between FIBs and lithium-ion batteries, the CoFe-F LDH is superior to most cathode materials for FIBs. Another important advantage of CoFe-F LDH FIBs is that they can work at room temperature, which has been rarely achieved in previous reports. The superior performance stems from the unique topochemical transformation property and small volume change (∼0.82%) of LDH in electrochemical cycles. Such a tiny volume change makes LDH a zero-strain cathode material for FIBs. The 2D diffusion pathways and weak interaction between fluoride ions and host layers facilitate the de/intercalation of fluoride ions, accompanied by the chemical state changes of Co2+/Co3+ and Fe2+/Fe3+ couples. First-principles calculations also reveal a low F- diffusion barrier during the cyclic process. These findings expand the application field of LDH materials and propose a novel avenue for the designs of cathode materials toward room-temperature FIBs.

Two-Dimensional Beidellite/Carbon Superlattice for Boosting Lithium-Ion Storage Performance.

Two-dimensional Fe-beidellite/carbon (Fe-BEI@C) superlattice-like heterostructure was prepared by intercalation of glucose in the gallery of layered Fe-BEI followed by calcination. The interlaminar and superficial carbon coating enables Fe-BEI to have good rate performance, fast lithium-ion diffusion, and high pseudocapacitance contribution, leading to excellent lithium storage performance as anode material for lithium-ion batteries (LIBs). The Fe-BEI@C/Li half cell delivers a maximum specific capacity of 850 mAh·g-1 at 0.5 A·g-1 and has a 92.3% retention rate after 100 cycles along with a high-rate performance of 403 mAh·g-1 at 5 A·g-1. The reversible valence state change of Si2+/Si4+ and Fe0/Fex+ (0 < x < 3) in electrochemical cycles are realized without collapse of layered structure. Additionally, the Fe-BEI@C heterostructure displays a high Li+ diffusion coefficient of 10-13∼10-10 cm2 s-1, illustrating fast Li+ transfer in the interlayer of Fe-BEI@C heterostructure. Dynamic analysis reveals that the Si redox reaction is almost dominated by surface control and that of Fe is mainly diffusion-controlled. This work has exploited a novel layered silicate as anode material for LIBs and developed a molecular-level carbon hybridization method to improve their electrochemical performance, which is meaningful for the application of layered silicate in the energy-storage field.