Rechargeable sodium metal batteries (SMBs) have emerged as promising alternatives to commercial Li‐ion batteries because of the natural abundance and low cost of sodium resources. However, the overuse of metallic sodium in conventional SMBs limits their energy densities and leads to severe safety concerns. Herein, we propose a sodium‐free‐anode SMB (SFA‐SMB) configuration consisting of a sodium‐rich Na superionic conductor‐structured cathode and a bare Al/C current collector to address the above challenges. Sodiated Na₃V₂(PO₄)₃ in the form of Na₅V₂(PO₄)₃ was investigated as a cathode to provide a stable and controllable sodium source in the SFA‐SMB. It provides not only remarkable Coulombic efficiencies of Na plating/stripping cycles but also a highly reversible three‐electron redox reaction within 1.0–3.8 V versus Na/Na⁺ confirmed by structural/electrochemical measurements. Consequently, an ultrahigh energy density of 400 Wh kg⁻¹ was achieved for the SFA‐SMB with fast Na storage kinetics and impressive capacity retention of 93% after 130 cycles. A narrowed voltage window (3.0–3.8 V vs. Na/Na⁺) further increased the lifespan to over 300 cycles with a high retained specific energy of 320 Wh kg⁻¹. Therefore, the proposed SFA‐SMB configuration opens a new avenue for fabricating next‐generation batteries with high energy densities and long lifetimes. image

Alkali metal batteries (AMBs) are promising next‐generation high‐density electrochemical energy storage systems. In addition, current collectors play important roles in enhancing their electrochemical performances. Thus, it is essential to have a critical review of the most recent advances in engineering the current collectors for high‐performance AMBs. In this review paper, the fundamentals of alkali metal deposition on current collectors will be introduced first. Then recent advances in the development of advanced metal and carbon‐based current collectors are examined for boosting the stability and cycle life of lithium metal batteries (LMBs) in terms of various strategies including 3D architectural design and functional modifications. Thereafter, the research progress in design of advanced current collectors will be analyzed for sodium/potassium metal batteries, especially the counterparts that do not follow the paradigms established in LMBs. Finally, the major challenges and key perspectives will be discussed for the future development of current collectors in AMBs. image

The ever‐growing pursuit of high energy density batteries has triggered extensive efforts toward developing alkali metal (Li, Na, and K) battery (AMB) technologies owing to high theoretical capacities and low redox potentials of metallic anodes. Typically, for new battery systems, the electrolyte design is critical for realizing the battery electrochemistry of AMBs. Conventional electrolytes in alkali ion batteries are generally unsuitable for sustaining the stability owing to the hyper‐reactivity and dendritic growth of alkali metals. In this review, we begin with the fundamentals of AMB electrolytes. Recent advancements in concentrated and fluorinated electrolytes, as well as functional electrolyte additives for boosting the stability of Li metal batteries, are summarized and discussed with a special focus on structure–composition–performance relationships. We then delve into the electrolyte formulations for Na‐ and K metal batteries, including those in which Na/K do not adhere to the Li‐inherited paradigms. Finally, the challenges and the future research needs in advanced electrolytes for AMB are highlighted. This comprehensive review sheds light on the principles for the rational design of promising electrolytes and offers new inspirations for developing stable AMBs with high performance.

Efficient capture of CO₂ and its conversion into other high value-added compounds by electrochemical methods is an effective way to reduce excess CO₂ in the atmosphere. Porous polymeric materials hold great promise for selective adsorption and electrocatalytic reduction of CO₂ due to their high specific surface area, tunable porosity, structural diversity, and chemical stability. Here, we review recent research advances in this field, including design of porous organic polymers (POPs), porous coordination polymers (PCPs), covalent organic frameworks (COFs), and functional nitrogen-containing polymers for capture and electrocatalytic reduction of CO₂. In addition, key issues and prospects for the optimal design of porous polymers for future development are elucidated. This review is expected to shed new light on the development of advanced porous polymer electrocatalysts for efficient CO₂ reduction.