• Energy Research

This literature review presents the recent development and deep insight into the understanding of Na metal anode for Na metal batteries.

Nitride solid-state electrolytes offer intrinsic stability with lithium metal and improved ionic conductivity. This review highlights advances in their design, synthesis, and application for enabling practical all-solid-state lithium metal batteries.

AbstractNa‐O2 batteries are advantageous as the candidates of next‐generation electric vehicles due to their ultrahigh theoretical energy density and have attracted enormous attention recently. Tremendous efforts have been devoted to improve the Na‐O2 battery performance by designing advanced electrodes with various carbon‐based materials. Carbon materials used in Na‐O2 batteries not only function as the air electrode to provide active sites and accommodate discharge products but also as Na anode protectors against dendrite growth and chemical/electrochemical corrosion. In this review, we mainly focus on the application of various carbon‐based materials in Na‐O2 batteries and highlight their advances. The scientific understanding on the fundamental design of the material microstructure and chemistry in relation to the battery performance are summarized. Finally, perspectives on enhancing the overall battery performance based on the optimization and rational design of carbon‐based cell components are also briefly anticipated.

AbstractLiFePO4 has been widely used as a cathode material in lithium ion batteries. However, some impurity phases existing in LiFePO4 have a significant influence on its electrochemical performance. Therefore, detection of the impurity phases is necessary for the manufacturer in order to improve the quality of LiFePO4. In particular, visualization of the impurity and secondary phase distributions immersed in the bulk LiFePO4 crystal can help to understand the origin of the impurity and secondary phases, providing clear guidance towards the synthesis of high purity LiFePO4. The results show that with the combination of Raman and EDS, we are capable of identifying the low melting lithium phosphate phase in LFP ingot. Through micro XRF mapping, more detailed information about the LFP materials after carbon coating are observed. The secondary phases are easily defined due to the high sensitivity of this technology.

Solid-state batteries have fascinated the research community over the past decade, largely due to their improved safety properties and potential for high-energy density. Searching for fast ion conductors with sufficient electrochemical and chemical stabilities is at the heart of solid-state battery research and applications. Recently, significant progress has been made in solid-state electrolyte development. Sulfide-, oxide-, and halide-based electrolytes have been able to achieve high ionic conductivities of more than 10-3 S/cm at room temperature, which are comparable to liquid-based electrolytes. However, their stability toward Li metal anodes poses significant challenges for these electrolytes. The existence of non-Li cations that can be reduced by Li metal in these electrolytes hinders the application of Li anode and therefore poses an obstacle toward achieving high-energy density. The finding of antiperovskites as ionic conductors in recent years has demonstrated a new and exciting solution. These materials, mainly constructed from Li (or Na), O, and Cl (or Br), are lightweight and electrochemically stable toward metallic Li and possess promising ionic conductivity. Because of the structural flexibility and tunability, antiperovskite electrolytes are excellent candidates for solid-state battery applications, and researchers are still exploring the relationship between their structure and ion diffusion behavior. Herein, the recent progress of antiperovskites for solid-state batteries is reviewed, and the strategies to tune the ionic conductivity by structural manipulation are summarized. Major challenges and future directions are discussed to facilitate the development of antiperovskite-based solid-state batteries.

Single-atom Pt sites stabilized by aniline stacked on graphene exhibit excellent electrocatalytic activity and durability for the hydrogen evolution reaction.

Developing high energy density batteries, such as metal–air systems, requires a good understanding of their underlying electrochemical principles.

This review summarizes the latest fundamental research advances on all-solid-state lithium batteries with sulfide electrolytes and provides an energy-density-oriented roadmap for practical solid-state pouch cells.