Yizhou Wang

Porous metallic current collectors can homogenize lithium (Li) deposition and accommodate volume change, but increasing porosity generally compromises mechanical integrity under stack pressure. Here, a mechanically reinforced, gradient‐designed hierarchical current collector (GDH CC) is constructed from an FeNi alloy skeleton, a conformal Cu shell, and Al ₂ O ₃ ‐modified outer faces. The FeNi‐containing framework reinforces the porous architecture while the spatially differentiated interfaces are designed to favor internal Li accommodation. The 50 µm‐thick CC combines a retained porosity of 80.13% with a compressive yield strength of 0.309 MPa and was examined after passing a nominal Li deposition charge of 8 mAh cm ⁻² . Cross‐sectional microscopy and in situ optical observations indicate center‐outward plating and reverse stripping within the scaffold. The GDH CC delivers an average Coulombic efficiency of 98.7% for 400 cycles at 1 mA cm ⁻² and 1 mAh cm ⁻² and supports stable bidirectional cycling in pouch‐type cells. A multilayer LFP | Li/GDH CC | LFP pouch cell delivers 145 mAh g ⁻¹ at 1 C, corresponding to cell‐level gravimetric and volumetric energy densities of 172.49 Wh kg ⁻¹ and 297.78 Wh L ⁻¹ , respectively. These results identify mechanical reinforcement as an important design dimension for high‐porosity Li hosts.

This review highlights the role of inter-flake structure in MXene-based sensing and discusses how spacing, orientation, porosity, and inter-flake chemistry can be controlled to influence its sensing performance.

Aqueous zinc‐ion batteries (AZIBs) are promising candidates for future large‐scale energy storage because of their high safety and low cost. However, dendritic Zn growth at the anode severely compromises its long‐term cyclability and thus impedes practical deployment of AZIBs. From a crystallographic perspective, enforcing preferential Zn growth along the (002) orientation can effectively suppress dendrite formation, but most existing strategies rely on pre‐texturing of anodes or substantially altering the electrolyte composition, both of which add additional complexity and cost. In this regard, achieving robust (002)‐oriented Zn deposition on commercial Zn foil in a ZnSO ₄ ‐dominated electrolyte remains crucial to the future development of AZIBs. Herein, we develop a new electrolyte additive, 2,4,6‐trimethoxy‐s‐triazine (TST), which functions at trace concentrations to enable (002)‐oriented Zn deposition at battery anodes. Via pre‐adsorption on the anode surface, TST promotes a hexagonally ordered Zn adlayer as an interfacial brick template, thereby enabling texture‐inherited (002) plating during subsequent electrodeposition. The proposed mechanism is corroborated through multi‐dimensional characterization, and the resulting Zn anodes deliver markedly improved cycling stability across multiple cell configurations. We believe this work can inspire future studies on crystallographic orientation engineering‐based Zn anode protection and can accelerate the practical implementation of AZIBs.

Li metal anodes are promising for next‐generation high‐energy batteries, but their practical use is hindered by dendritic Li growth, unstable interfaces, and large volume fluctuations. Herein, we report a bidirectional sandwich‐structured Li metal anode (SLA) fabricated through a solvent‐free rolling and pressing strategy. The SLA integrates an ultrathin Li layer with thermally stable 3D Cu nanowire networks on both sides, forming a lightweight, flexible, and mechanically robust electrode. The interconnected Cu nanowire framework provides continuous electron pathways, homogenizes current distribution, and accommodates Li volume changes, thereby guiding uniform Li deposition and stripping within the electrode interior. Benefiting from this design, the SLA achieves a high Coulombic efficiency of 98.73% over 250 cycles at 1 mA cm ⁻² and 1 mAh cm ⁻² , while symmetric cells operate stably for over 1350 h with low polarization. Full cells paired with high‐loading NCM811 cathodes deliver excellent cycling stability and rate capability. For a 4‐layer stacked pouch cell, the SLA‐based system delivers a gravimetric energy density of 279.11 Wh kg ⁻¹ and a volumetric energy density of 470.52 Wh L ⁻¹ , outperforming the PLA counterpart. This work provides a simple strategy for advancing stable Li metal anodes and high‐energy‐density Li metal batteries.

Lithium metal batteries promise exceptional energy density but remain constrained by nonuniform Li deposition, severe volume fluctuations, and localized electrochemical‐thermal instability. Here, an ultralight conductive‐gradient current collector (UCG CC) is developed to spatially orchestrate ionic, electronic, and thermal transport through an asymmetric fibrous architecture. The UCG CC is fabricated by unilaterally depositing Cu onto a porous polyacrylonitrile nanofiber membrane, producing a Cu‐rich conductive region with a gradual decrease in Cu content across the electrode thickness. The cyano‐rich fibrous scaffold homogenizes Li ⁺ flux, whereas the interconnected Cu network redistributes electron transport, lowers local current density, and facilitates lateral heat dissipation. This spatially differentiated transport architecture directs Li nucleation toward the Cu‐rich bottom region and enables progressive pore filling, thereby suppressing separator‐facing Li accumulation and accommodating electrode‐volume variation. With an areal density of only 1.24 mg cm ⁻² , the UCG CC enables stable Li plating/stripping for over 2000 h in symmetric cells. Li/UCG CC||LFP full cells retain 82.66% of their capacity after 300 cycles, while pouch cells exhibit stable operation, homogeneous temperature evolution. This work establishes a mass‐efficient fibrous current‐collector platform for coordinating ion‐electron‐thermal transport in high‐energy lithium metal batteries.

MXenes, a family of two‐dimensional (2D) transition‐metal carbides and nitrides, offer a compelling combination of metallic conductivity and tunable surface chemistry. However, their potential as electrical contacts for p ‐type 2D semiconductors remains largely untapped. Here, we systematically investigate the role of MXene composition by comparing Ti ₃ C ₂ T _x , Nb ₂ CT _x , and Mo ₂ CT _x as contacts for p ‐type 2H‐MoTe ₂ transistors. Through a polymer‐assisted transfer process that ensures high‐quality interfaces, we identify Nb ₂ CT _x as the best‐performing contact material among the MXenes examined in this work, attributed to its superior band alignment, which markedly reduces contact resistance compared to both conventional metals and other MXenes. Consequently, Nb ₂ CT _x /2H‐MoTe ₂ field‐effect transistors achieve a high hole mobility of approximately 17 cm ² V ⁻¹ s ⁻¹ and an on/off current ratio exceeding 10 ³ . Temperature‐dependent measurements further reveal a near‐ideal interface, with a Schottky barrier height of only a few millielectronvolts under strong gate bias. These findings establish compositional engineering of MXenes as a powerful strategy for designing electrode–semiconductor interfaces and position Nb ₂ CT _x as a scalable, high‐performance contact material for advancing p ‐type 2D electronics.

Aqueous zinc (Zn)‐ion batteries (AZIBs) hold great promise for large‐scale energy storage owing to their high theoretical volumetric capacity, intrinsic safety, and environmental benignity. However, the strong Zn ²⁺ ‐H ₂ O coordination in conventional electrolytes induces dendrite growth, hydrogen evolution, and passivation, severely limiting reversibility and cycling stability. Herein, a molecular functionalization strategy using zinc tetraphenylporphyrin (ZnTPP) is proposed to achieve coupled regulation of Zn ²⁺ solvation and interfacial reaction kinetics. The π‐conjugated planar structure and pyrrolic nitrogen atoms of ZnTPP provide dual functions: the nitrogen atoms strongly coordinate with Zn ²⁺ to weaken Zn ²⁺ ‐H ₂ O interactions and reduce desolvation barriers, while the conjugated plane adsorbs on the Zn surface to redistribute local charge density and suppress dendritic nucleation. Combined experimental and theoretical analyses reveal that ZnTPP stabilizes the primary solvation shell, increases the hydrogen evolution overpotential, and decreases the corrosion current density. Furthermore, ZnTPP increases the Zn ²⁺ transference number from 0.39 to 0.77, thereby mitigating concentration polarization and facilitating ion transport. This, in turn, lowers the charge‐transfer resistance and enables preferential Zn deposition along the thermodynamically favorable (002) facet, ultimately leading to uniform and compact Zn deposits. This study elucidates the porphyrin‐induced solvation‐interface coupling mechanism and offers a molecular design strategy for stable, high‐performance AZIBs.

MXene, a family of 2D transition‐metal carbides, nitrides, or carbonitrides, uniquely integrates metallic conductivity, surface tunability, and compositional versatility, enabling their widespread applications across energy, electronics, sensors, and environmental systems. Beyond conventional optimization (e.g., composition, termination, defects), a new research frontier has recently emerged that focuses on engineering the orientation of MXene flakes, i.e., the deliberate control of flake alignment within MXene‐based structures such as fibers, films, membranes, and gels. Engineered orientation transforms inherently disordered MXene assemblies into highly anisotropic structures with directionally optimized electron, ion, and stress transport pathways. Compared with their randomly stacked counterparts, these oriented MXene structures exhibit remarkably enhanced electrical, ionic, and mechanical properties, unlocking new routes to tailor the macroscopic performance of MXene‐based devices. This review aims to provide a comprehensive and systematic summary of the orientation engineering of MXene flakes, covering the fundamental properties governed by MXene flake orientation, characterization techniques for revealing MXene orientation information, fabrication methodologies for achieving engineered MXene orientation, representative advances of oriented MXene structures in diverse functional systems, and forward‐looking design opportunities for MXene orientation engineering. This article offers both a concise knowledge framework and forward‐looking insights for inspiring the rational design of next‐generation MXene‐based materials and devices.

Aqueous batteries have played a pivotal yet fluctuating role in the evolution of electrochemical energy storage. From their foundational success in lead–acid and nickel‐based chemistries to their eclipse by lithium‐ion batteries, aqueous systems were long regarded as technologically inferior due to limited energy density and poor cycling stability. However, the urgent demand for safe, low‐cost, and sustainable storage has sparked a renaissance, fueled by breakthroughs in electrolyte engineering and advanced electrode materials for both anodes and cathodes. This review revisits the historical trajectory of commercialized aqueous batteries, extracting lessons from past successes and failures while highlighting the technological advances that now enable extended voltage windows, improved cycling stability, and scalable manufacturing. We argue that the future of aqueous batteries lies not in directly competing with lithium‐ion in high‐energy applications, but in complementing them across grid‐scale storage, uninterruptible power supplies, and decentralized energy systems where safety, cost, and recyclability are paramount. By connecting history with current progress, we reflect on how these insights reshape expectations for the next generation of aqueous batteries and their role in a more diversified and sustainable energy storage landscape.

The orientation of MXene flakes has received increasing research attention as it plays a critical role in determining the performance of MXene‐based assemblies. Engineering MXene flakes into horizontal or vertical orientations can offer distinct advantages such as higher electrical conductivity, higher mechanical strength, and more efficient ion/molecule transport across the flakes. However, the benefits of horizontal and vertical orientations are mutually exclusive, and both of them possess structural symmetry that restricts their ability for stimuli‐responsive deformation. Herein, a Janus‐oriented MXene fiber is reported, consisting of vertically oriented flakes on one side and horizontally oriented ones on the other. The unique Janus orientation endows the fiber with good mechanical properties, high electrical conductivity, and asymmetric volume expansion capability. Interestingly, such asymmetric volume expansion between the two orientations induces a pronounced curling deformation under water stimuli, leading to a high length change of up to 2100%. Due to such a strong deformation response, the Janus MXene fiber is used to construct an event‐triggered logic gate, which enables the operation of a dual‐mode water immersion warning system featuring both light and Bluetooth signaling. This work is believed to provide inspiration for future orientation engineering of MXene flakes and the design of advanced MXene‐based information devices.