A polymer solid electrolyte incorporating UIO66-NH2 (UN66) filler functionalized with the ionic liquid EMIM (IL-UN66) exhibits high ionic mobility and excellent electrochemical stability. The IL-UN66 filler plays a dual role: it effectively anchors TFSI- anions to promote rapid Na+ transport, while simultaneously facilitating the formation of an inorganic-rich solid-electrolyte interphase and enhancing the thermal stability of the polymer membrane. This integrated design enables reliable solid-state sodium-ion batteries with superior cycling stability.

A schematic of NaHMDS as a sacrificial sodium source for highly reversible anode-free sodium batteries with stable SEI/CEI interphases and dendrite-free deposition.

NASICON-type Na3.5V1.5Mn0.5(PO4)3 (NVMP) is a cost-effective cathode candidate for sodium-ion batteries (SIBs). Nevertheless, its practical deployment is hindered by sluggish reaction kinetics and severe structural degradation. Herein, by incorporating synergistic dopants (Al, Ni, Zr) into transition metal sites, a Na3.5V1.35Mn0.5Al0.05Ni0.05Zr0.05(PO4)3/C (NVMANZP) is constructed. This multi-cation substitution increases configurational entropy, fundamentally altering the inherent biphasic reaction (in pristine NVMP) to a predominantly solid-solution-like mechanism in NVMANZP, which reduces the Na+ migration barrier and accelerates reaction kinetics. Moreover, this entropy-stabilized mechanism minimizes Jahn-Teller lattice strain, enhancing cycling stability. Consequently, NVMANZP delivers 118.3 mAh g-1 at 0.2C (1C = 110 mA g-1), retains 77.3 mAh g-1 at 100C (vs. 52.4 mAh g-1 for pristine), and maintains 80.76% capacity retention after 4,000 cycles at 10C. The full cell achieves 378 Wh kg-1 at 0.2C (based on mass of cathode). This work establishes NVMANZP as a high-rate, long-life SIB cathode and reveals how entropy-driven mechanisms tailor NASICON reaction kinetics.

Aqueous zinc-ion batteries hold great promise for safe and sustainable energy storage, but their practical deployment is severely hindered under extreme temperatures by electrolyte freezing, intensified corrosion, and hydrogen evolution. Herein, we propose a dual-mixing high-entropy strategy that simultaneously introduces multiple cations (Zn2+, Mg2+, Ca2+, and Li+) and organic solvents (dimethyl sulfoxide and acetone) into a ZnCl2-based aqueous electrolyte. This synergistic design significantly amplifies configurational entropy, effectively disrupting the hydrogen-bond network and suppressing ice nucleation, achieving an extremely low glass transition temperature of -105 degrees C without detectable crystallization. The highly disordered solvation structure reduces water activity, suppresses parasitic side reactions, and stabilizes the zinc-electrolyte interface, enabling highly uniform and dendrite-suppressed zinc deposition. Consequently, the dual-mixing electrolyte enables stable symmetric cell cycling for over 1400 h at -40 degrees C and 1600 h at 30 degrees C. Zn||polyaniline full cells deliver over 1000 cycles across -40 degrees C to 50 degrees C, retaining 72% capacity even at 50 degrees C. This work demonstrates that dual-mixing high-entropy design is a promising strategy for all-climate aqueous zinc-ion batteries.

Reconciling fast-charging kinetics with high initial Coulombic efficiency (ICE) in biomass-derived hard carbon (HC) anodes for sodium-ion batteries (SIBs) remains a formidable challenge due to the intrinsic trade-off between accessible porosity and severe interfacial side reactions. Herein, a topological distortion strategy via molecular regulation is proposed to comprehensively engineer hard carbon materials. This tailored pyrolytic pathway yields a unique carbon architecture with an abundant and highly distorted closed-pore network. Internally, the highly curved carbon layers and closed pores establish unhindered bicontinuous highways for ultrafast Na+ diffusion and electron transport, deeply unlocking kinetic limitations in the plateau region. Externally, the specifically distorted surface creates localized microenvironments that promote the specific adsorption of PF6- anions, catalyzing the in-situ formation of an ultrathin and NaF-rich anion-guided interphase. This advanced interphase facilitates rapid Na+ desolvation while thoroughly suppressing continuous irreversible electrolyte consumption. Consequently, the optimized anode achieves an exceptional ICE of 92.6% with a large reversible capacity of 321 mAh g-1 in an ether-based electrolyte. Impressively, it unlocks ultrafast sodium storage, retaining 200 mAh g-1 even at a stringent current density of 5000 mA g-1, and demonstrating outstanding full-cell viability. This work elucidates the critical interplay among precursor chemistry, topological defects, and SEI engineering, offering a molecular blueprint for next-generation power-type SIBs.

Lithium manganese iron phosphate (LMFP) is a promising cathode material for lithium-ion batteries (LIBs) due to its cost-effectiveness, high safety, and high-energy density. However, its practical deployment is critically hindered by sluggish Li+ diffusion kinetics. Herein, we propose to utilize Zr4+ as a lattice bond-stiffness topological optimizer to reconstruct the atomic interaction landscape of LiMn0.7Fe0.3PO4. Through precise charge compensation and local strain engineering, the Zr4+ dopant induces a unique stiff-skeleton/flexible-ion topological configuration. Specifically, it shortens the Mn/Fe & horbar;O bonds to rigidify the polyanionic framework against distortion, while simultaneously elongating the Li & horbar;O bonds to weaken the electrostatic confinement of Li+. Consequently, this bond-stiffness modulation effectively decouples the tradeoff between structural stability and ionic mobility. The optimized LMZ0.015FP cathode delivers superior reversible capacities of 166.99, 136.13, and 119.01 mAh g-1 at 0.1, 20, and 50 C, respectively, along with outstanding cycling stability (99.6% retention after 300 cycles at 1 C). Even in a graphite||LMZ0.015FP full cell, a high capacity retention of 97.3% is maintained after 150 cycles. This work demonstrates that lattice bond-stiffness topological engineering not only accelerates Li+ diffusion kinetics and promotes a solid-solution reaction pathway but also establishes a rational paradigm for designing next-generation fast-charging polyanionic cathodes.

Electrolytic Zn–MnO2 batteries are promising candidates for safe and sustainable energy storage owing to their high voltage, environmental benignity, and cost-effectiveness. However, practical applications are hindered by the poor conductivity and the irreversible dissolution of conventional ε-MnO2 deposits. Herein, we report a scalable semisolid slurry electrode architecture that enables stable MnO2 deposition/dissolution using a three-dimensional percolating network of carbon nanotubes (CNTs) as both conductive matrix and deposition host. The slurry system promotes the formation of highly conductive γ-MnO2 owing to enhanced charge transfer kinetics, enabling overall dissolution rather than the localized separation typically seen in traditional electrodes. The Zn–MnO2 slurry cell exhibits a reversible areal capacity approaching 60 mAh cm−2. Moreover, the flowable nature of the slurry allows electrochemically inactive MnO2 formed during dissolution to be reconnected and reactivated by CNTs in the rheological network, ensuring deep utilization and cycling stability. This work establishes a slurry electrode strategy to improve electrolytic MnO2 reactions and offers a viable pathway toward renewable aqueous batteries for grid-scale applications.

Aqueous zinc-powder slurry batteries hold significant promise for large-scale energy storage owing to their simple manufacturing, design flexibility, and high reactivity. However, their high water content and the reactive nature of zinc powder exacerbate parasitic side reactions and sluggish Zn2+ migration kinetics. Therefore, 3-mercapto-1-propanesulfonate is incorporated into a polyacrylamide-based slurry. The zincophilic additive can disrupt the strong Zn2+-H2O coordination and preferentially adsorb onto zinc powder surfaces, constructing a Zn2+-enriched interface that facilitates ion transport and reduces polarization. As a result, the Zn||Zn symmetric cell delivers an ultralong cycling stability exceeding 1200 h, and the NH4V4O10 full cell maintains a high capacity retention of 80% after 1000 cycles at 4 A g-1. This work offers a coordination-chemistry-guided strategy for designing aqueous zinc slurry anodes with enhanced stability and reversibility.

Anode-free sodium metal batteries (AFSMBs) remove the excess metal anode and increase projected cell-level energy density, but they place reversibility on a transient negative-electrode interface. In each cycle, Na is deposited on a foreign current collector and removed to a highly depleted state. Cell failure is governed by whether continuity can be preserved across a sequence of short-lived interfacial states, including bulk coordination, interfacial desolvation, heterogeneous nucleation, metallic coalescence, Na isolation, and recurrent solid electrolyte interphase (SEI) renewal. AFSMBs are therefore better understood as dynamically reconstructed interfacial systems, where non-uniformity introduced during interfacial entry can propagate through later plating and stripping. This review examines AFSMBs through three coupled stages: solvation-controlled interfacial entry, current collector regulated Na reconstruction, and SEI renewal controlled by reaction-pathway selectivity and mechanical coherence. Current density, stripping depth, pressure, temperature, sodium inventory, and cell architecture are treated as boundary conditions that determine whether local interfacial gains persist under practical operation. By linking coordination chemistry, metallic continuity, interphase renewal, and device-level constraints, this review provides a mechanistic framework for predictive AFSMB design.

The rational design of electrolyte additives for aqueous zinc-ion batteries is currently hindered by the lack of quantifiable theoretical descriptors. Herein, we employ the hard-soft acid-base (HSAB) theory as a guiding principle for molecular engineering. Using 3-mercaptopropionic acid (MPA) as a model molecule, we propose a “solution-interface dual-site coupling” strategy to realize the synergistic remodeling of the bulk-to-interface environment. According to the HSAB principle, Zn2+ acts as a hard acid, preferentially binding to the hard carboxylate oxygen of MPA. This coordination tailors the primary solvation shell, which decreases the desolvation barrier and inhibits parasitic hydrogen evolution. Concurrently, sulfhydryl moiety functions as a soft base and undergoes preferential specific adsorption on the metallic Zn anode, which exhibits soft-acid characteristics. This interaction anchors an oriented organic shield, thereby homogenizing the local electric field distribution and inhibiting dendritic growth. Consequently, both symmetric and full cells using the MPA-containing electrolyte exhibit improved cycling stability. This work demonstrates HSAB theory as a generalizable and experimentally verifiable molecular-design framework for rationally screening multifunctional additives in aqueous Zn-based batteries.

A boron-modified glass fiber separator was fabricated by magnetron sputtering. The highly zincophilic boron layer homogenizes Zn2+ distribution to inhibit dendrite growth, and its strong binding with SO42- restrains adverse side reactions. This modification strategy enables high-performance aqueous zinc-ion batteries.

The practical application of composite solid-state sodium metal batteries is critically limited by poor organic-inorganic compatibility, causing particle agglomeration, high interfacial resistance, and dendrite growth. Here, a covalent surface grafting strategy constructs a multifunctional interlayer covalently anchored on Na3Zr2Si2PO12, featuring a cross‑linked siloxane network and terminal ─NH2 groups. Covalent anchorage transforms inert particle surfaces into dispersible units, while ─NH2 groups anchor TFSI- and confine residual solvent via hydrogen bonding and Lewis acid‑base interactions. This dual regulation decouples ion transport from side reactions, yielding a high Na+ transference number (0.58) and a stable, NaF‑rich, thin solid‑electrolyte interphase (SEI). The optimized electrolyte enables symmetric cells with exceptional cycling stability and high critical current density (CCD). Full cells achieve fast‑charging (92 mAh g-1 at 15 C) and ultralong cycle life (76.4% retention after 7000 cycles at 10 C). A flexible pouch cell retains 97% capacity after 150 cycles. This work establishes that precise molecular‑level interfacial design, rather than simple physical blending, is key to high‑performance, dendrite‑resistant solid‑state sodium batteries.

Sodium-metal batteries (SMBs) are seen as a promising energy storage option due to their high energy density, abundant sodium resources, and cost-effectiveness. However, traditional organic liquid electrolytes (LEs) suffer from inherent safety risks, including leakage and flammability. Solid polymer electrolytes (SPEs) are regarded as a viable alternative to LEs for safer SMBs. However, the poor interfacial contact and insufficient ion transport associated with conventional ex situ prepared SPEs make it difficult for them to outperform LEs. The in situ polymerization technique, characterized by its process scalability and ability to form conformal interfaces, has proven effective in overcoming the obstacles associated with SPEs. In this review, we summarize recent research on in situ polymerization techniques for SMBs, including free-radical polymerization, ionic polymerization, electropolymerization, and related approaches. The importance of in situ polymerization in streamlining the preparation process, enhancing the compatibility of the electrode-electrolyte interface, bolstering battery safety, and optimizing electrochemical performance is highlighted. Furthermore, we systematically discuss the multiscale design principles of this technology, emphasizing precursor formulation, reaction kinetics, and targeted bulk-matrix properties. The advanced functional applications of in situ polymerization in SMBs, particularly in suppressing crosstalk effects, regulating solvation structures, and designing artificial interfacial layers and materials, are discussed. Finally, critical challenges, future prospects and pathways toward the practical, large-scale application of in situ polymerization are evaluated. This review aims to provide systematic insights to facilitate the rapid progress and implementation of in situ-polymerized electrolytes in SMBs.

Hetero-Li + regulates Na + solvation through competitive coordination in a same-anion electrolyte, enabling the formation of a hierarchical Na-rich/LiF-rich interphase and highly reversible Na plating/stripping in anode-free sodium batteries.

Conductive carbon blacks (CCBs) are indispensable for electron-conducting networks in sodium-ion batteries (SIBs), yet their intrinsic electrochemical activities and impact on the solid electrolyte interphase (SEI) remain critically overlooked. This work decouples the microstructures of three commercial CCBs-Acetylene Black (AB), Super P (SP), and Ketjen Black (KB)-and their dynamic interfacial chemistries. Advanced cryo-electron microscopy visualizes that CCBs act beyond passive conductors, actively dictating local SEI formation. Defective SP and highly porous KB trigger massive electrolyte decomposition, generating thick organic layers and Na2O-rich byproducts, respectively. In contrast, highly crystalline AB selectively induces an ultrathin, incomplete Na2CO3-based SEI, which preserves intrinsic particle conductivity and minimizes interfacial impedance. As standalone anodes, AB delivers a superior reversible capacity of 194 mAh g-1, significantly outperforming SP (152 mAh g-1) and KB (130 mAh g-1). Translating this advantage into practice, a hard carbon anode formulated with 10 wt% AB achieves an exceptional initial capacity of 324 mAh g-1 with 72% initial Coulombic efficiency and robust cycling stability (321 mAh g-1 after 100 cycles). This stands in stark contrast to the inferior efficiencies (∼64%) and severe capacity fading induced by SP and KB additives. This work provides a critical paradigm for formulating high-efficiency sodium-ion batteries.

Aqueous manganese-based batteries with deposition-dissolution mechanism offer advantages including abundant material sources, low cost and intrinsic safety. However, the continuous accumulation of inactive Mn species during cycling suppresses the reversibility of the Mn2+/MnO2 reaction, and the resulting ion de-intercalation reactions reduce the energy density, hindering the practical application of manganese-based batteries. Herein, we reveals that inactive Mn species primarily arises from the fracture and detachment of the MnO2 deposition layer from the carbon fiber surface during extended cycling. We constructed a flexible carbon nanotube (CNT) framework on the cathode substrate which effectively prevents the fracture of the deposition layer caused by the volume expansion during the liquid-solid phase transition of the Mn2+/MnO2 reaction, thus preventing the formation of inactive Mn species at the source. Compared with the conventional Cu-MnO2 cells with the pristine carbon felt substrate which exhibit a Coulombic efficiency below 95 %, the cells assembled with the CNT framework substrate achieve 98 % Coulombic efficiency and increased energy efficiency from 75 % to 80 %. This simple and effective optimization strategy may further promote the application of high-energy manganese-based batteries in large-scale energy storage.

The practical deployment of NASICON-based solid-state sodium batteries is critically hindered by persistent challenges of poor interfacial compatibility, low sintered density, and unstable grain boundaries that facilitate dendrite growth. To address these intertwined limitations of Na3Zr2Si2PO12 (NZSP) solid-state electrolyte (SSE), we propose a precisely targeted doping strategy with multicomponent sites. By substituting the Zr-sites with Y3+, Ti4+ and Fe3+ and the Si/P-sites with Al3+ and B3+ cations, we successfully introduce substantial polyhedral distortion and partial amorphization. This yields a novel triphasic SSE, whose microstructure comprises a crystalline NASICON main phase, an amorphous phase, and a grain boundary-modified NaAlSi3O8 (NASO) secondary phase. This unique microstructural design concurrently enhances interfacial stability, densification, and dendrite suppression. The low-melting-point NASO phase acts as an in situ sintering aid, enabling superior densification at a reduced processing temperature of 1000 °C and effectively eliminating continuous, highly resistive grain boundaries. More importantly, the NASO phase optimizes the interfacial electronic structure, significantly raising the energy barrier for dendrite nucleation. Consequently, the optimized SSE achieves enhanced ionic conductivity and interfacial compatibility, supporting stable, dendrite-free sodium plating/stripping for over 5000 h in symmetric cells. When paired with a Na3V2(PO4)3 (NVP) cathode, the full cell demonstrates outstanding rate capability and unprecedented cycling stability, retaining 83% of its capacity after 3000 cycles at 2 C. This work establishes a viable design pathway for developing high-performance and durable oxide SSEs toward next-generation solid-state sodium metal batteries.

Harnessing anionic oxygen redox is pivotal for boosting the capacity of O3-type layered transition metal oxides for sodium ion batteries (SIBs), yet it often triggers severe lattice distortion and irreversible oxygen release. Herein, we propose an in situ electrochemical surface reconstruction strategy to stabilize the O3-type NaNi1/3Fe1/3Mn1/3O2 (NFM) cathode. By strictly controlling the initial anionic redox reactions at an ultra-high potential of 4.6 V, a robust heterostructure comprising an ordered layered core and a disordered rocksalt shell is constructed. This unique surface architecture serves as an isotropic strain buffer that effectively mitigates particle cracking and provides dense surface passivation to suppress interfacial side reactions. Furthermore, the induced rocksalt phase stabilizes the surface TM-O coordination, thereby preventing lattice oxygen loss during subsequent cycling. Consequently, when cycled within 2.0-4.0 V, the electrochemically pretreated cathode (DRS(4.6)@NFM) exhibits significantly reduced lattice distortion and superior electrochemical durability (capacity retention ratio of 90.77% after 300 cycles) with negligible voltage decay (retaining 98.56% of the initial voltage). Even when cycled up to 4.2 V, a capacity retention ratio of 87.4% after 300 cycles is still maintained. This work elucidates the interplay between electrochemical pretreatment and structural evolution, providing a decisive foundation for designing high-voltage and durable sodium-ion cathodes.

Rational design high-performance electrode modification materials with enhanced electron transport rate, reduced oxidation overpotential and improved selectivity is essential to achieve high-performance sensors. In this work, we established a straightforward synthesis method for producing delta-MnO2 nanoflowers with abundant pores, anchored on electrochemical reduced graphene oxide (delta-MnO2-ERGO). This configuration not only ensures the accessibility of catalytic sites but also facilitates efficient electron transport and mass transfer during catalytic reactions. Notably, the flower-like delta-MnO2, characterized by a prominently exposed (-111) crystal plane, enhances its oxidative performance toward tryptophan (Trp). As a result, the delta-MnO2-ERGO/GCE demonstrated an unexpected performance for quantitative determination of Trp with the linear range 6.0 nM similar to 1.0 mu M and 1.0 mu M similar to 10 mu M, and a low detection limit (4.0 nM, S/N = 3). Furthermore, the sensor proved effective for Trp analysis in pharmaceutical preparations, human serum and urine, yielding satisfactory outcomes. These findings provide significant insights into the synthesis of flower-like delta-MnO2 as highly efficient catalyst and their application in electrochemical sensors.