Abnormal Ionic Conductivities in Halide NaBi 3 O 4 Cl 2 Induced by Absorbing Water and a Derived Oxhydryl Group

Recent progress and strategic perspectives of inorganic solid electrolytes: fundamentals, modifications, and applications in sodium metal batteries

Solid-state electrolytes (SEs) have attracted overwhelming attention as a promising alternative to traditional organic liquid electrolytes (OLEs) for high-energy-density sodium-metal batteries (SMBs), owing to their intrinsic incombustibility, wider electrochemical stability window (ESW), and better thermal stability. Among various kinds of SEs, inorganic solid-state electrolytes (ISEs) stand out because of their high ionic conductivity, excellent oxidative stability, and good mechanical strength, rendering potential utilization in safe and dendrite-free SMBs at room temperature. However, the development of Na-ion ISEs still remains challenging, that a perfect solution has yet to be achieved. Herein, we provide a comprehensive and in-depth inspection of the state-of-the-art ISEs, aiming at revealing the underlying Na⁺ conduction mechanisms at different length scales, and interpreting their compatibility with the Na metal anode from multiple aspects. A thorough material screening will include nearly all ISEs developed to date, i.e., oxides, chalcogenides, halides, antiperovskites, and borohydrides, followed by an overview of the modification strategies for enhancing their ionic conductivity and interfacial compatibility with Na metal, including synthesis, doping and interfacial engineering. By discussing the remaining challenges in ISE research, we propose rational and strategic perspectives that can serve as guidelines for future development of desirable ISEs and practical implementation of high-performance SMBs.

CS-CNTs homojunctions prepared byin situgrowth of carbon nanotubes on the surface of porous carbon spheres for lithium-sulfur batteries

Lithium-sulfur battery is expected to become a new generation of commercial battery owing to its ultra-high theoretical specific capacity, low-cost, and environmental benign. However, the inherent insulation of sulfur and the shuttle effect of lithium polysulfide between electrodes limit the application of lithium-sulfur battery. In order to solve these problems, we focus on the design of carbon-sulfur composite structure. Herein, CS-CNTs homojunctions featured with the carbon nanotubes (CNTs)in situgrown on carbon sphere (CS) is designed and synthesized by simple polymerization and heat treatment. The composites of CS with interconnected pore networks and CNTs with high conductivity not only offer a conductive framework to promote fast electron transmission, but also provide a larger space to load sulfur and effectively capture polysulfides. The CS-CNTs@S cathode shows better electrochemical performance compared with CS-CPs@S and CS@S. The first discharge specific capacity is 1053 mAh g^-1at 0.1 C. After 200 cycles, the specific capacity still remains at 427 mAh g^-1.

Electrochemical Driven Phase Segregation Enabled Dual-Ion Removal Battery Deionization Electrode

Battery deionization (BDI) offers a powerful platform for integrating water treatment and energy conversion. Exploring novel BDI electrode materials with high energy storage capacity and high efficiency for both cations and anions removal is the key to advancing the BDI technique. Herein, we report the first BDI electrode material capable of simultaneously removing Cl^- (58.4 mg g^-1) and Na⁺ (8.7 mg g^-1) in water with a reversible capacity of 160 mAh g^-1. In situ powder X-ray diffraction (PXRD) unravels that the dual-ion removal capability is attributed to a novel reversible electrochemical driven phase segregation reaction mechanism between NaBi₃O₄Cl₂ and the in situ formed metallic Bi. The unique dual-ion storage capability demonstrated with the NaBi₃O₄Cl₂ electrode indicates that exploring electrochemical reversible phase segregation electrode material holds great promise for advancing the BDI electrode for future desalination techniques and aqueous rechargeable battery systems.