Qi Yang

Carbon materials with superior porosity and conductivity are widely adopted in aqueous zinc–iodine batteries to host iodine, but suffer from the polyiodide shuttle and cycling stability challenges. Traditional strategies mainly focus on pore structure engineering or heteroatom doping of carbon hosts to confine iodine, but fail to address the sluggish iodine conversion kinetics. Herein, we initially reveal the significant yet overlooked role of hybridization state in reforming the carbon intrinsic activity toward high-efficiency iodine conversion chemistry. With pitch-derived porous carbon as an example, we controllably regulate the C(sp2)/C(sp3) ratio (from 1.23 to 2.21) while maintaining high surface area. These properties lower the activation energy of iodine conversion and effectively suppress the polyiodide shuttle. The zinc–iodine battery exhibits ultrahigh cycling stability after 150,000 cycles and a low self-discharging rate with only 12.5% capacity loss after 20 days. Ah-level pouch cell with 66.6 mgiodine cm–2 achieves a cumulative discharging capacity of 103.51 Ah. The hybridization engineering was successfully extended to commercial porous carbon (YP-50F), prolonging the lifespan from 7425 to 27,000 cycles. This work presents a hybridization state engineering strategy to reform the intrinsic activity of the carbon host to favor the iodine conversion chemistry and beyond.

Conventional low-temperature aqueous electrolytes are primarily designed to suppress electrolyte freezing and thereby preserve ion transport in the liquid state, but such strategies become ineffective once electrolyte solidification becomes unavoidable. Here, we report an aqueous phase-transition electrolyte (PTE) that preserves intimate electrode–electrolyte contact and exhibits high ionic conductivity after solidification. Systematic characterization reveals that the solidified PTE consists of an interconnected ice framework permeated by a continuous liquid electrolyte, whereas a conventional ZnSO4-based electrolyte (ZSBE) forms isolated salt domains within the ice matrix, resulting in poor interfacial contact and limited ionic transport. This unique architecture establishes continuous ion-transport pathways throughout the solidified electrolyte, enabling an ionic conductivity of 1.870 mS cm–1 at −60 °C, compared to only 0.065 mS cm–1 for ZSBE. Using an aqueous Zn||I2 battery as a model system, PTE affords exceptional cycling stability and rate capability at low temperatures, achieving a record-high cycling lifespan of 430 000 cycles at 40 A g–1 and −40 °C. An Ah-level pouch cell remains operational in liquid nitrogen, powering 107 light-emitting diodes. This work marks a paradigm shift from preventing electrolyte freezing to sustaining high ionic conductivity after solidification for low-temperature aqueous batteries.

Organo‐interhalogen‐mediated four‐electron iodine conversion (I ⁻ /I ⁰ /I ⁺ ) promises high‐energy Zn batteries (4eZIBs) in noncorrosive aqueous electrolytes. Yet, polyiodide shuttling and I ⁺ hydrolysis restrict shorten cycle life at high iodine loadings. Here we report a dual‐anionic Hofmeister‐regulated amide‐protonated polyacrylamide (pPAM) hydrogel electrolyte to solve this issue. Consistent with experimental observations, underlying mechanistic interpretations are proposed. The potential protonated site ─COHNH ₂ ⁺ in pPAM can interact with iodine species (I ₃ ⁻ , I ₂ , and organo‐interhalogen adduct), effectively suppressing active material loss during cycling. The dual‐anion‐regulated Hofmeister effect may contribute to control molecular mediator (2‐bromoacetamide, BrAce) flux within the pPAM gel, enabling fast organo‐interhalogen conversion. The extensive hydrogen‐bonding network of the hydrogel reshapes the hydrogen‐bonding environment of water, suppressing organo‐interhalogen adduct (I ⁺ species) hydrolysis. The resulting quasi‐solid‐state 4eZIBs substantially outperform aqueous counterparts and state‐of‐the‐art results. At 15.6 mg cm ⁻² iodine loading, stable cycling exceeds 2000 cycles at 15 mA cm ⁻² . At 28.3 mg cm ⁻² , the battery delivers an areal capacity of 9.95 mAh cm ⁻² and an areal energy density of 10.85 mWh cm ⁻² . An Ah‐level pouch cell cycles 50 times at 0.5 mA cm ⁻² , with an energy density of 305.27 Wh kg _iodine ⁻¹ . This work provides a hydrogel design principle for organo‐interhalogen‐mediated conversion, advancing practical high‐loading 4eZIBs and beyond.

Organo‐interhalogen‐mediated four‐electron iodine conversion (I ⁻ /I ⁰ /I ⁺ ) promises high‐energy Zn batteries (4eZIBs) in noncorrosive aqueous electrolytes. Yet, polyiodide shuttling and I ⁺ hydrolysis restrict shorten cycle life at high iodine loadings. Here we report a dual‐anionic Hofmeister‐regulated amide‐protonated polyacrylamide (pPAM) hydrogel electrolyte to solve this issue. Consistent with experimental observations, underlying mechanistic interpretations are proposed. The potential protonated site ─COHNH ₂ ⁺ in pPAM can interact with iodine species (I ₃ ⁻ , I ₂ , and organo‐interhalogen adduct), effectively suppressing active material loss during cycling. The dual‐anion‐regulated Hofmeister effect may contribute to control molecular mediator (2‐bromoacetamide, BrAce) flux within the pPAM gel, enabling fast organo‐interhalogen conversion. The extensive hydrogen‐bonding network of the hydrogel reshapes the hydrogen‐bonding environment of water, suppressing organo‐interhalogen adduct (I ⁺ species) hydrolysis. The resulting quasi‐solid‐state 4eZIBs substantially outperform aqueous counterparts and state‐of‐the‐art results. At 15.6 mg cm ⁻² iodine loading, stable cycling exceeds 2000 cycles at 15 mA cm ⁻² . At 28.3 mg cm ⁻² , the battery delivers an areal capacity of 9.95 mAh cm ⁻² and an areal energy density of 10.85 mWh cm ⁻² . An Ah‐level pouch cell cycles 50 times at 0.5 mA cm ⁻² , with an energy density of 305.27 Wh kg _iodine ⁻¹ . This work provides a hydrogel design principle for organo‐interhalogen‐mediated conversion, advancing practical high‐loading 4eZIBs and beyond.

Aqueous zinc‐iodine (Zn||I ₂ ) batteries, combining inherent safety and environmental friendliness, hold great promise for large‐scale energy storage. However, the system faces an unstable Zn interface and insufficient iodine utilization. Herein, we propose 1‐ethyl‐3‐methylimidazolium bromide (EMBr) functions as a Lewis acid‐base additive to promote anode and cathode stability in aqueous Zn||I ₂ batteries. Specifically, the EM ⁺ cation of EMBr stabilizes the Zn metal anode (ZMA) by forming water‐poor Helmholtz double layer, inhibiting water‐induced side reactions. This enables the ZMA with excellent cyclic stability of 2100 h and a high average Coulombic efficiency of 98.73%, superior to its counterpart (100 h and 95.7%). EM ⁺ cation also effectively captures polyiodide species, inhibiting polyiodide shuttle. Meanwhile, the Br ⁻ anion facilitates I ⁻ /I ⁰ /I ⁺ conversion reactions by forming interhalogen compounds. The synthetic Fe ₃ C loaded on the ZIF8 derived carbon (ZFeC) is selected as the host material because of its catalytic activity. The Zn|EMBr|ZFeC‐I ₂ batteries with multi‐electron conversion reactions achieve 52 000 cycles with 324.3 mAh g ⁻¹ , equivalent to ∼2.5 times that of Zn|EMBr|ZC‐I ₂ batteries at 5 A g ⁻¹ . Besides, ZFeC shows a pseudocapacitance proportion of 94.8% higher than ZC (85.6%), achieving quick conversion reaction kinetics. This work offers a versatile Lewis acid‐base paradigm for practical high‐valence aqueous zinc‐based batteries.

Multi‐electron redox conversion cathode materials offer substantial promise for the development of high‐energy batteries. However, the pervasive challenges of soluble redox intermediates, usually causing severe shuttling and rapid self‐discharge, have long plagued almost all established conversion systems, including halogens, chalcogens, and pnictogens, across various electrolyte systems. Herein, for the first time, we unlock SiO as a high‐energy and sustainable conversion cathode with near‐zero shuttle and ultralow self‐discharge, via reversible two‐electron Si(II)/Si(IV) oxychloride conversion chemistry in nucleophilic ionic liquid (IL) electrolytes. When coupled with a Zn metal anode, the full cell delivers a specific capacity of 915 mAh g ⁻¹ _SiO at 0.05 A g ⁻¹ (75.3% of theoretical limit: 1215 mAh g ⁻¹ _SiO ), featuring a flat voltage plateau at 1.2 V and an ultrahigh energy density of ca. 1100 Wh kg ⁻¹ _SiO . Remarkably, the system exhibits negligible shuttle behavior during 500 cycles, with a daily average self‐discharge rate of only 0.8% over 15 days, significantly surpassing conventional conversion cathodes (e.g., halogens, chalcogens, and pnictogens). After 920 cycles at 1 A g ⁻¹ , capacity retention remains at 92.7% with well‐kept voltage plateaus. This work decodes a new family of high‐energy conversion cathodes, which could be extended to other multivalent metal‐ion (e.g., Al ³⁺ ) batteries.

The synthesis of nanoscale high-entropy alloys (nHEAs) with customized elements is severely constrained by the intrinsic immiscibility of metal elements, leading to phase separation. Current methods for making nHEAs via high-temperature treatment or liquid metals often suffer from element selection or particle size control. Herein, we report a carbon-directed methodology that overcomes these limitations by directly modulating the mixing enthalpy. We establish a linear correlation between mixing enthalpy and charge transfer, providing a mechanistic pathway to circumvent element immiscibility. Specifically, hydrogen-substituted graphdiyne (HsGDY), characterized by its unique sp1–sp2 cohybridization, acts as an electron redistributor to exchange electrons with metal atoms, thereby driving the mixing enthalpy toward zero to form nHEAs. This enables HsGDY to outperform conventional sp2 carbons in mediating interface interactions for the growth of nHEAs with tuned particle sizes. This approach is universal, validated by the precise synthesis of 5–15-element nHEAs with ultrasmall size (∼3 nm) at a relatively low temperature of 423 K. The resulting nHEAs exhibit exceptional catalytic activity and stability for the hydrogen evolution reaction (HER), surpassing state-of-the-art benchmarks. This carbon-directed synthesis paradigm paves a new way to high-entropy alloys for catalysis and beyond.

Prussian blue analogues (PBAs) are promising cathode materials for Zn‐ion batteries (ZIBs) due to their open framework and high operating voltage. However, the blocked long‐range ion transport caused by structural collapse during the repeated ion intercalation/deintercalation at high loading mass remains a critical issue to address in practical applications. Here, we propose the promotion of long‐range ion transport in model cathode of Mn/Fe‐based PBAs by solvent intercalation, which expands the ion channel and regulates the coordination number of Fe active center. This suppresses the lattice oscillation related to the evolution between Fe ²⁺ ‐C≡N‐M ²⁺ and Fe ³⁺ ‐C≡N‐M ³⁺ and decreases the ion long‐range transport barrier under high loading mass. Consequently, it achieves a capacity enhancement of 185% at 9 mg cm ⁻² and good cycling stability at 18 mg cm ⁻² , surpassing other reported PBAs cathodes in ZIBs. This study provides a new direction for addressing the high‐loading‐mass challenge of PBAs cathode for ZIBs.

Efficient ion desolvation and rapid mass transport are crucial yet often competing requirements for stabilizing Zn anodes in aqueous Zn‐ion batteries. This dilemma arises because ion desolvation introduces additional energy barriers that increase ion diffusion resistance. To reconcile this inherent trade‐off, a hydrogen‐bonded organic framework (HOF) based on C ₃ ‑symmetric trigonal carboxyl ligands is engineered as an ion‐sieving interface. This design integrates precise pore size control with tailored chemical environment to regulate Zn ²⁺ desolvation behavior. As expected, the flexible HOF incorporating an electron‐deficient triazine core (HOF‐TAT) dynamically strips solvated water molecules while maintaining continuous ion flux. This process fosters a gradient solid electrolyte interphase that synergizes with the self‐adaptive porous framework to guide dense (101)‐oriented Zn deposition. The HOF‐TAT@Zn symmetric cells stably cycle exceeding 3400 h at 5 mA cm ⁻² . Furthermore, the iodophilic porous framework immobilizes shuttling polyiodides through strong physicochemical interactions. When integrated with an ultrathin Zn anode (10 µm), the Zn‐iodine batteries deliver a high‐rate capacity (142.2 mAh g ⁻¹ at 5 A g ⁻¹ ) and long‐term lifetime (50 000 cycles). This work offers an intelligent strategy to concurrently overcome the high energy barriers of ion desolvation and the kinetic limitations of ion transport for building advanced electrochemical devices.

Efficient ion desolvation and rapid mass transport are crucial yet often competing requirements for stabilizing Zn anodes in aqueous Zn‐ion batteries. This dilemma arises because ion desolvation introduces additional energy barriers that increase ion diffusion resistance. To reconcile this inherent trade‐off, a hydrogen‐bonded organic framework (HOF) based on C ₃ ‑symmetric trigonal carboxyl ligands is engineered as an ion‐sieving interface. This design integrates precise pore size control with tailored chemical environment to regulate Zn ²⁺ desolvation behavior. As expected, the flexible HOF incorporating an electron‐deficient triazine core (HOF‐TAT) dynamically strips solvated water molecules while maintaining continuous ion flux. This process fosters a gradient solid electrolyte interphase that synergizes with the self‐adaptive porous framework to guide dense (101)‐oriented Zn deposition. The HOF‐TAT@Zn symmetric cells stably cycle exceeding 3400 h at 5 mA cm ⁻² . Furthermore, the iodophilic porous framework immobilizes shuttling polyiodides through strong physicochemical interactions. When integrated with an ultrathin Zn anode (10 µm), the Zn‐iodine batteries deliver a high‐rate capacity (142.2 mAh g ⁻¹ at 5 A g ⁻¹ ) and long‐term lifetime (50 000 cycles). This work offers an intelligent strategy to concurrently overcome the high energy barriers of ion desolvation and the kinetic limitations of ion transport for building advanced electrochemical devices.