The feasibility of the commercialization of lithium-sulfur (Li-S) batteries is troubled by sluggish redox conversion kinetics and the shuttle effect of polysulfides. Herein, a zeolitic imidazolate framework derived amorphous CoP combined with carbon nanotubes conductive network composites (aCoP@CNTs) has been synthesized as an effective dual-electrocatalyst for accelerating the redox kinetics of polysulfides to prolong the lifespan of Li-S batteries. Compared with crystalline CoP, unsaturated Co atoms of aCoP@CNTs exhibit stronger chemical adsorption capacity for polysulfides and serve as catalytic centers to accelerate the conversion from soluble polysulfides to solid-state lithium sulfide. Meanwhile, the 3D porous conductive network not only facilitates ion/electron transportation but also forms a physical barrier to limit the migration of polysulfides. Benefiting from the above preponderances, the batteries with aCoP@CNTs modified interlayer exhibited excellent cycle stability (initial discharge capacity of 1227.9 mAh g^-1 at 0.2 C), rate performance (795.9 mAh g^-1 at 2.5 C), long-term cycle reliability (decay rate of 0.049% per cycle at 1 C over 1000 cycles), and superior high-loading performance (high initial discharge capacity of 886 mAh g^-1 and 753.6 mAh g^-1 at 1 C under high S loading of 3 mg cm^-2 and 4 mg cm^-2).

Lithium (Li) metal-based rechargeable batteries hold significant promise to meet the ever-increasing demands for portable electronic devices, electric vehicles and grid-scale energy storage, making them the optimal alternatives for next-generation secondary batteries. Nevertheless, Li metal anodes currently suffer from major drawbacks, including safety concerns, capacity decay and lifespan degradation, which arise from uncontrollable dendrite growth, notorious side reactions and infinite volume variation, thereby limiting their current practical application. Numerous critical endeavors from different perspectives have been dedicated to developing highly stable Li metal anodes. Herein, a comprehensive overview of Li metal anodes regarding fundamental mechanisms, scientific challenges, characterization techniques, theoretical investigations and advanced strategies is systematically presented. First, the basic working principles of Li metal-based batteries are introduced. Specific attention is then paid to the fundamental understanding of and challenges facing Li metal anodes. Accordingly, advanced characterization approaches and theoretical computations are introduced to understand the fundamental mechanisms of dendrite growth and parasitic reactions. Recent key progress in Li anode protection is then comprehensively summarized and categorized to generate an overview of the respective superiorities and limitations of the various strategies. Furthermore, this review concludes the remaining obstacles and potential research directions for inspiring the innovation of Li metal anodes and endeavors to accomplish the practical application of next-generation Li-based batteries.

Li-O₂ batteries show high energy storage potential, but there remain many material challenges that must be solved to fully develop them into a robust technology. The reactivity of the electrolyte against lithium metal as the anode or with oxygen superoxide radicals in the cathode is the main problem that may be alleviated by the use of ionic liquids and solid electrolytes. In this work, iongel solid flexible electrolytes with facile preparation are designed based on five variations of the successful N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide ionic liquid. These iongels show an outstanding ionic conductivity of 7.8 × 10^-3 S·cm^-1 at 25 °C, excellent performance against lithium metal and reduced dendritic growth, even at a high current density rate of 2 mA·cm^-2. Tests on Li-O₂ cells show a 100% capacity retention for 25 cycles with limited capacity. Hence, this work provides a plausible pathway to tackle the design of effective lithium protection methods and efficient solid electrolytes for Li-O₂ batteries.

Quasi-two-dimensional (2D) lead halide perovskites have emerged as promising candidates for improving the environmental stability of perovskite solar cells (PSCs). Herein, we report the preparation of a new quasi-2D perovskite by introducing a fluorine-containing additive [3-(trifluoromethyl)benzylammonium iodide (3-TFMBAI)] into Cs_0.17FA_0.83Pb(I_0.83Br_0.17)₃. The moderate doping of 3-TFMBAI effectively induces the formation of the Ruddlesden-Popper perovskite phase, which can passivate the trap states and restrain the ionic motion in the perovskite lattice. The constructed 3-(trifluoromethyl)benzylamine molecular planes with strong hydrophobicity favorably suppress the decomposition and collapse of the perovskite phase against humidity. Moreover, the introduction of Cs⁺ and Br^- ions tune the bandgap and improve the absorption, crystallinity and thermal stability of the perovskite films. As a result, a champion photoelectric conversion efficiency (PCE) of 20.89% is achieved, along with an improved open-circuit voltage reaching 1.22 V. The quasi-2D PSCs without encapsulation maintain 90.7% of the initial PCE after 1000 h under continuous heating at 60 °C and simultaneous exposure to humid air with a relative humidity of 60%. Four-terminal tandem solar cells are fabricated by combining top semi-transparent quasi-2D PSCs with bottom monocrystalline silicon solar cells, achieving an overall PCE of 23.53% and favorable performance stability.

With the fullness of time, metallic lithium (Li) as an anode could become highly promising for high-energy-density batteries. Theoretically, using Li metal as the negative electrode can result in higher theoretical capacity and lower oxidation voltage and density than in current commercially available batteries. During the charge/discharge process, however, metallic Li shows unavoidable drawbacks, such as dendritic growth, causing capacity degradation and a solid electrolyte interphase (SEI) layer derived from the side reactions between the Li metal anode and the electrolyte, resulting in depletion of the electrolyte. The formation of a suitable SEI is crucial to avoid the side reactions at the interface by circumventing direct contact. Unavoidable dendritic growth at the Li metal anode can be controlled by its ionic conductivity. Furthermore, the SEI is also required as a mechanical reinforcement for withstanding the volume change and suppressing dendritic growth in the Li metal anode. A limiting factor due to complex SEI formation must be considered from the perspectives of chemical and mechanical properties. To further enhance the cycling performance of Li metal batteries, an in-depth understanding of the SEI needs to be achieved to clarify these issues. In this mini review, we focus on the SEI, which consists of various deposited components, and discuss its ionic conductivity and mechanical strength for applications in electric vehicles.

The lithium-sulfur (Li-S) battery has been attracting much more attention in recent years due to its high theoretical capacity and low cost, although various issues, such as the “shuttle effect” and the low use ratio of active materials, have been hindering the development and application of Li-S batteries. The separator is an important part of Li-S batteries, and its modification is a simple and effective strategy to improve the electrochemical performance of Li-S batteries. In this work, we explore separators with different functions on their two sides that have been produced by a step-by-step electrospinning method. The multifunctional separator on one side is pure gelatin, and the other side is zeolitic imidazolate framework-67 (ZIF-67)-C₆₀-gelatin. The ZIF-67-C₆₀-gelatin layer on the cathode side is of great importance. The chemisorption sites on it are provided by ZIF-67, and the transformation sites of lithium polysulfide are provided by C₆₀. Gelatin, which is on the anode side, as an admirable separator material, makes the lithium flux uniform and thus prevents the generation of lithium dendrites. This type of multifunctional nanofiber separator based on double gelatin layers plays an important role in the adsorption and conversion of polysulfides, and it improves the overall performance of the Li-S battery. As a result, the Li-S batteries assembled with the prepared separator can still maintain the capacity of 888 mAh g^-1 after 100 cycles at 0.2 C, and the capacity retention rate of the Li-S batteries is 72.9% after 400 cycles at 2 C. This simple preparation method and high-performance bilayer membrane structure provide a new route for commercial application.

Zn-based electrochemistry is considered to be the most promising alternative to Li-ion batteries due to its abundant reserves and cost-effectiveness. In addition, aqueous electrolytes are more convenient to be used in Zn-based batteries due to their good compatibility with Zn-chemistry, thereby reducing cost and improving safety. Furthermore, Zn²⁺/Zn couples involve two-electron redox chemistry, which can provide higher theoretical energy capacity and energy density. Based on this, a series of Zn-based battery systems, including Zn-ion batteries, Zn-air batteries, and Zn-based redox flow batteries, have received more and more research attention. Here, the fundamentals and recent advances in Zn-based rechargeable batteries are presented, along with perspectives on further research directions.

Cobalt hexacyanoferrate (CoHCF) is one of the most promising cathode materials for all-climate sodium-ion batteries (SIBs) due to its open three-dimensional (3D) framework structures, high theoretical specific capacity, good voltage platform and almost no Jahn-Teller effects. However, CoHCF still suffers from poor cycling stability and bad rate capability, which is closely related to the huge distortion of frame structure and poor conductivity. In this study, by choosing nickel (Ni) to partially replace cobalt (Co) in the CoHCF lattice, we successfully prepared low-defect and Na-enriched Na₂Co_0.7Ni_0.3[Fe(CN)₆] (Co_0.7Ni_0.3HCF) in chelate and sodium salt-assisted coprecipitation method. Both experiments and first-principles calculations demonstrate that Ni substitution can effectively suppress the lattice distortion during the charging and discharging process of CoHCF. Furthermore, the introduction of Ni increases ion mobility by reducing the ion migration barrier (0.31 eV versus 0.17 eV) and improves the electronic conductivity by reducing the bandgap. It is found that Co_0.7Ni_0.3HCF exhibits superior electrochemical performance compared with that of CoHCF in a wide temperature range (-30 to 60 °C). At 25 °C, Co_0.7Ni_0.3HCF delivers a high specific capacity of 142.2 mAh g^-1 at 0.2 C, an ultrahigh rate capability with 126.2 mAh g^-1 at 5 C and excellent cycling stability with 80.9% capacity retention after 500 cycles at 5 C. Even at -30 °C, Co_0.7Ni_0.3HCF can provide a high capacity of 109 mAh g^-1 without an activation process. This work reveals the great application prospect of PBAs for all-climate SIBs, especially at low temperatures.

The significant market for electric vehicles and portable electronic devices is driving the development of high-energy-density solid-state lithium batteries. However, the solid electrolyte is still the main obstacle to the development of solid-state lithium batteries, mainly due to the lack of a single solid electrolyte that is compatible with both high-voltage cathodes and lithium metal anodes. These problems can potentially be solved with multilayer electrolytes. The property of each layer of the electrolyte can be tuned separately, which not only meets the different needs of the cathode and anode but also makes up for the shortcomings of each layer of the electrolyte, thereby achieving good mechanical properties and chemical and electrochemical stability. This review first presents a brief introduction to homogeneous single-layer electrolytes. The design principles of multilayer polymer electrolytes and the application of these principles using examples from recent work are then introduced. Finally, several suggestions as guides for future work are given.