Anode-free sodium-ion batteries (AFSIBs) achieve energy storage by completely eliminating traditional anode active materials and relying solely on the reversible plating and stripping of sodium from the anode source onto the current collector surface. This approach fundamentally addresses the limitations of energy density and safety inherent in conventional sodium batteries, positioning it as a promising candidate for high-energy “super-lithium” electrochemical storage technology. However, this innovative design also places unprecedentedly stringent demands on the current collector, making it a critical component in determining cell performance. This review systematically outlines the prevailing methodologies and research progress on modifying collectors for AFSIBs, with a focus on material sodophilicity engineering and structural modulation. By comprehensively reviewing the process of different sodium-friendly material modifications, interfacial functional modulation, porous structure configuration, and gradient engineering on the cell performance, the essential elements for enhancing the electrochemical performance of the current collector are outlined. Building on this, the paper discusses the challenges and opportunities in this field and suggests new research directions for developing high-performance AFSIBs.

Smart sensors for detecting biochemical substances are desired for various applications such as wearable electronics, diagnosis, and environmental monitoring. For the past decades, the rapid development of nanomaterials has enabled significant improvement of sensing devices based on the nanomaterials, due to their superior physical and chemical properties. However, sensing platforms with good sensitivity, selectivity, stability, and facile fabrication processes suitable for mass production are still a challenge. MXenes (e.g., transition metal carbides, nitrides, and carbonitrides), among those potential candidates for sensing materials, show promising potential with their intrinsically two-dimensional large interactive area, wide-range-tunable material properties, active surface chemistry, and excellent processability for large-scale fabrication. Here, we provide a critical review of the MXene-based sensing technologies. The synthesis strategies and material properties are systematically summarized. The working mechanisms corresponding to the material structure for MXene-based sensors are classified into subcategories and discussed respectively. The representative works are analyzed, and performance-enhancing strategies are revisited and summarized. Finally, the challenges that hinder MXene-based bio/chemical sensors from commercialization and the outlook on the further development of MXene sensing electronics are presented.

Polyoxometalates (POMs) are considered highly suitable for electrochemical energy storage due to their advantageous structural and electrochemical features. As inorganic molecular clusters, POMs exhibit high thermal and chemical stability, tunable redox potentials, and a wide range of compositions, making them attractive for use in electrochemical storage devices. This work systematically explores the unique advantages of POMs-based materials, including their redox reactions and charge storage mechanisms. The introduction of conductive polymers into electrochemical devices shows remarkably enhanced performance, and the assembled solid-state capacitor 1-CC@PANI-SC achieved a maximum specific capacitance of 86.8 mAh g⁻¹, an energy density of 14.16 Wh kg⁻¹ with power density of 802.57 W kg⁻¹. This study provides a promising insight for the design and synthesis of purely inorganic POMs and applications in energy storage devices.

In₂O₃-based TFTs have garnered widespread attention due to their higher mobilities than amorphous silicon. Previous studies have indicated that rare earth doping can enhance the NBIS stability of TFTs, but this often results in a decrease in mobility. To improve the mobility of TFTs while maintaining stability, we incorporated Mo and Pr into In₂O₃, fabricating InPrMoO TFTs. Mo doping is believed to positively affect In₂O₃ through reducing porosity and defects. Pr doping has been proposed as a potential strategy to enhance the NBIS stability of In₂O₃. A nondestructive μPCD detector was employed to characterize the local defect states of the film. X-ray photoelectron spectroscopy data demonstrate that the InPrMoO film with 0.8 mol% Mo doping has the lowest concentration of oxygen vacancies (Vo). TFTs fabricated using the InPrMoO film doped with an optimized concentration of 0.8 mol% Mo exhibit superior electrical properties (μ_sat = 12.2 cm²/V·s, V_th = 1.6 V, I_on/I_off = 2.17 × 10⁶, and SS = 0.47 V/dec) and the minimal ΔV_th under NBS/PBS/NBIS = −0.65 V/0.79 V/−0.70 V. The synergistic effect of Mo and Pr doping has led to enhanced film uniformity and density, consequently improving the mobility and stability of the TFTs. To tackle the challenge of predicting optimal process parameters, a multiobjective prediction model integrating physical models and machine learning was developed. The predicted optimal parameters (0.78 mol% Mo doping, 381°C annealing) were experimentally verified, yielding < 5% relative error in most film properties. The prepared TFT exhibits a mobility of 13.5 cm²/V·s (10.6% improvement), an on/off current ratio of 3.82 × 10⁶, and an SS of 0.40 V/dec, demonstrating superior efficiency over conventional trial-and-error methods.

The widespread deployment of rechargeable lithium-, sodium-, and potassium-ion batteries (PIBs) is critically constrained by safety concerns, particularly those associated with the flammability of conventional carbonate-based electrolytes. In response, the development of non-flammable electrolyte systems has emerged as a key strategy to mitigate thermal runaway risks and ensure the safe operation of energy storage devices. This review provided a comprehensive overview of recent advances in non-flammable electrolytes, with a focus on their chemical design, thermal stability, electrochemical performance, and compatibility with battery components. Various classes of flame-retardant materials were systematically examined, including organophosphorus compounds, halogenated solvents, ionic liquids, aqueous systems, and solid-state electrolytes. Special attention was given to the molecular mechanisms underlying flame suppression and interfacial stability, as well as strategies for balancing safety with high energy density. By summarizing state-of-the-art developments and identifying remaining challenges, including cost-effectiveness, compatibility with high-voltage electrodes, and long-term cycling stability, this review aimed to guide the rational design of intrinsically safe, high-performance battery systems for next-generation energy technologies.

The proton exchange membrane (PEM) is critical for the operation of proton exchange membrane fuel cells (PEMFCs). However, cationic impurities (e.g., Ca²⁺ and Mg²⁺) in water or the environment readily bind to the PEM's sulfonic acid groups (−SO₃H), deactivating sites and reducing proton conductivity. This necessitates costly and high-precision water treatment. Conventional solutions, such as adding perfluorosulfonic acid (PFSA) chains or anti-hardness additives often raise costs and lower intrinsic conductivity. To address this issue, we developed a novel multilayer casting technique. This method used airborne moisture to drive −SO₃H group migration toward surfaces while simultaneously densifying fluorocarbon chains into a robust network. Repeated casting cycles created an internal multilayered barrier network within the PEM. This structure generated effective steric hindrance, physically blocking cation diffusion and significantly boosting hard water resistance. Performance tests demonstrated that after 4 h of heated immersion in 220 ppm hard water, the proton conductivity (8.0 S/m) maintained a value of 294%, which was higher than that of N117. The technique also established a gradient distribution of hydrophilic domains across the membrane. This optimized proton transport pathways enabling the MLM to achieve proton conductivity comparable to commercial Nafion membranes under standard conditions. This provided a path to more durable and cost-effective PEMFCs.