PVDF-HFP@Nafion-based quasisolid polymer electrolyte for high migration number in working rechargeable Na-O2 batteries.

Rechargeable sodium-oxygen (Na-O2) battery is deemed as a promising high-energy storage device due to the abundant sodium resources and high theoretical energy density (1,108 Wh kg-1). A series of quasisolid electrolytes are constantly being designed to restrain the dendrites growth, the volatile and leaking risks of liquid electrolytes due to the open system of Na-O2 batteries. However, the ticklish problem about low operating current density for quasisolid electrolytes still hasn't been conquered. Herein, we report a rechargeable Na-O2 battery with polyvinylidene fluoride-hexafluoropropylene recombination Nafion (PVDF-HFP@Nafion) based quasisolid polymer electrolyte (QPE) and MXene-based Na anode with gradient sodiophilic structure (M-GSS/Na). QPE displays good flame resistance, locking liquid and hydrophobic properties. The introduction of Nafion can lead to a high Na+ migration number (tNa+ = 0.68) by blocking the motion of anion and promote the formation of NaF-rich solid electrolyte interphase, resulting in excellent cycling stability at relatively high current density under quasisolid environment. In the meantime, the M-GSS/Na anode exhibits excellent dendrite inhibition ability and cycling stability. Therefore, with the synergistic effect of QPE and M-GSS/Na, constructed Na-O2 batteries run more stably and exhibit a low potential gap (0.166 V) after an initial 80 cycles at 1,000 mA g-1 and 1,000 mAh g-1. This work provides the reference basis for building quasisolid state Na-O2 batteries with long-term cycling stability.

Directional electronic tuning of Ni nanoparticles by interfacial oxygen bridging of support for catalyzing alkaline hydrogen oxidation.

Metallic nickel (Ni) is a promising candidate to substitute Pt-based catalysts for hydrogen oxidation reaction (HOR), but huge challenges still exist in precise modulation of the electronic structure to boost the electrocatalytic performances. Herein, we present the use of single-layer Ti3C2Tx MXene to deliberately tailor the electronic structure of Ni nanoparticles via interfacial oxygen bridges, which affords Ni/Ti3C2Tx electrocatalyst with exceptional performances for HOR in an alkaline medium. Remarkably, it shows a high kinetic current of 16.39 mA cmdisk-2 at the overpotential of 50 mV for HOR [78 and 2.7 times higher than that of metallic Ni and Pt/C (20%), respectively], also with good durability and CO antipoisoning ability (1,000 ppm) that are not available for conventional Pt/C (20%) catalyst. The ultrahigh conductivity of single-layer Ti3C2Tx provides fast transmission of electrons for Ni nanoparticles, of which the uniform and small sizes endow them with high-density active sites. Further, the terminated -O/-OH functional groups on Ti3C2Tx directionally capture electrons from Ni nanoparticles via interfacial Ni-O bridges, leading to obvious electronic polarization. This could enhance the Nids-O2p interaction and weaken Nids-H1s interaction of Ni sites in Ni/Ti3C2Txenabling a suitable H-/OH-binding energy and thus enhancing the HOR activity.

Spin-Magnetic Effect of d-π Conjugation Polymer Enhanced O-H Cleavage in Water Oxidation.

A deep understanding of the mechanism for the spin-magnetic effect on O-H cleavage is crucial for the development of new catalysts for water oxidation. Herein, we designed and synthesized the crystalline Fe-DABDT and Co-DABDT (DABDT = 2,5-diaminobenzene-1,4-dithiol) and optimized an effective magnetic moment to explore the role of the spin-magnetic effect in the regulation of water oxidation activity. It can be found that the OER activity of the catalyst is positively correlated with its effective magnetic moment. Under the external magnetic field, Fe-DABDT with more spin single electrons has a stronger spin-magnetic response to water oxidation than Fe/Co-DABDT and Co-DABDT. The increase in OER current of Fe-DABDT is nearly 2 times higher than that of Co-DABDT. Experimental and density functional theory studies show that magnetized Fe sites could realize nucleophilic reaction, accelerate the polarization of electron spin states, and promote the polar decomposition of O-H and the formation of the O-O bond. This study provides mechanistic insight into the spin-magnetic effect of oxygen evolution reaction and further understanding of the spin origin of catalytic activity, which is expected to improve the energy efficiency of hydrogen production.

Sustainable Aqueous Batteries Based on Bipolar Dissociation of Aluminum Hydroxyacetate Electrolyte.

Rechargeable aqueous batteries are potential systems for large-scale energy storage due to their high safety and low cost. However, developing aqueous batteries with high sustainability, affordability, and reversibility is urgent and challenging. Here we report an amphoteric aluminum hydroxyacetate (AlAc(OH)2) electrolyte with the ability of bipolar ionization of H+ and OH-, which facilitates the redox reactions at both the anthraquinone (AQ) anode and nickel hydroxide (Ni(OH)2) cathode. The bipolar ionization ability of the AlAc(OH)2(H2O)3 solvation structure results from the strong polarization ability of Al3+ and OH-. The H+/OH- dissociation ability with a dissociation constant of 5.0/3.0 is stronger than that of water (14.0), which boosts the simultaneous stable redox reactions of electrodes. Specifically, H+ uptake prevents the AQ anode from the formation of an ionic bond, suppressing the electrode dissolution, whereas OH- provides the local alkaline environment for the stable conversion reaction of the Ni(OH)2 cathode. The AQ anode in the designed AQ||Ni(OH)2 battery delivers a discharge capacity of 243.9 mAh g-1 and a capacity retention of 78.2% after 300 cycles with high reversibility. Moreover, a pouch cell with a discharge capacity of 0.90 Ah was assembled, exhibiting an energy density of 44.7 Wh kg-1 based on the total mass of the battery. This work significantly widens the types of aqueous batteries and represents a design philosophy of bipolar electrolytes and distinct electrochemical reactions with H+ and OH-.

Uncovering the Crucial Role of Chelating Structures in Cyano-Alkyl-Phosphate Electrolytes for High-Voltage Lithium Metal Batteries.

The inferior oxidative stability of commercial carbonate electrolytes and overgrowth of the electrode-electrolyte interphase (EEI) have largely hindered the development of high-voltage lithium metal batteries. In this study, these challenges are addressed by designing Li+-solvent chelating solvation structures to inhibit solvent decomposition using cyano-alkyl-phosphate as a demonstration. Theoretical and experimental studies confirm that the -P═O and -C≡N groups within diethyl (2-cyanethyl) phosphonate exhibit a comparable ability to coordinate with Li+, facilitating the formation of seven-membered chelating structures. This unique solvation structure contributes to the formation of anion-derived inorganic-rich EEI with high stability and robustness, hindering the further decomposition of the electrolyte. Additionally, the cyano group has a strong complexation with the transition metal (TM) in the cathode to inhibit TM dissolution, thereby ensuring the structural stability of the cathode particle. Utilizing this special chelating structure, the designed electrolyte demonstrates favorable Li plating/stripping reversibility and promising oxidative stability in high-voltage batteries. Consequently, the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode exhibits a high capacity retention (90%) after operating 300 cycles. Under harsh testing conditions, the 4.6 V Li||NCM811 pouch cell with a capacity of 1.4 Ah (∼295 Wh kg-1 based on the total mass of the cell) retains 70% capacity after 80 cycles. This work provides new insights into the correlation between the solvation structure and oxidative stability of electrolytes, contributing significantly to the advancement of high-voltage lithium metal batteries.

Solid-State Electrolytes by Electrospinning Techniques for Lithium Batteries.

Solid-state lithium batteries (SSLBs) are regarded as next-generation energy storage devices because of their advantages in terms of safety and energy density. However, the poor interfacial compatibility and low ionic conductivity seriously hinder their development. Electrospinning is considered as a promising method for fabricating solid-state electrolytes (SSEs) with controllable nanofiber structures, scalability, and cost-effectiveness. Numerous efforts are dedicated to electrospinning SSEs with high ionic conductivity and strong interfacial compatibility, but a comprehensive summary is lacking. Here, the history of electrospinning SSEs is overeviewed and introduce the electrospinning mechanism, followed by the manipulation of electrospun nanofibers and their utilization in SSEs, as well as various methods to improve the ionic conductivity of SSEs. Finally, new perspectives aimed at enhancing the performance of SSEs membranes and facilitating their industrialization are proposed. This review aims to provide a comprehensive overview and future perspective on electrospinning technology in SSEs, with the goal of guiding the further development of SSLBs.

Hierarchical Sea Urchin-like Fe-doped Heazlewoodite for High-Efficient Oxygen Evolution.

Electrochemical water-splitting to produce hydrogen is potential to substitute the traditional industrial coal gasification, but the oxygen evolution kinetics at the anode remains sluggish. In this paper, sea urchin-like Fe doped Ni3S2 catalyst growing on nickel foam (NF) substrate is constructed via a simple two-step strategy, including surface iron activation and post sulfuration process. The NF-Fe-Ni3S2 obtains at temperature of 130 °C (NF-Fe-Ni3S2-130) features nanoneedle-like arrays which are vertically grown on the particles to form sea urchin-like morphology, features high electrochemical surface area. As oxygen evolution catalyst, NF-Fe-Ni3S2-130 exhibits excellent oxygen evolution activities, fast reaction kinetics, and superior reaction stability. The excellent OER performance of sea urchin-like NF-Fe-Ni3S2-130 is mainly ascribed to the high-vertically dispersive of nanoneedles and the existing Fe dopants, which obviously improved the reaction kinetics and the intrinsic catalytic properties. The simple preparation strategy is conducive to establish high-electrochemical-interface catalysts, which shows great potential in renewable energy conversion.

Emerging electrolytes with fluorinated solvents for rechargeable lithium-based batteries.

Electrolytes that can ensure the movement of ions and regulate interfacial chemistries for fast mass and charge transfer are essential in many types of electrochemical energy storage devices. However, in the emerging energy-dense lithium-based batteries, the uncontrollable side-reactions and consumption of the electrolyte result in poor electrochemical performances and severe safety concerns. In this case, fluorination has been demonstrated to be one of the most effective strategies to overcome the above-mentioned issues without significantly contributing to engineering and technical difficulties. Herein, we present a comprehensive overview of the fluorinated solvents that can be employed in lithium-based batteries. Firstly, the basic parameters that dictate the properties of solvents/electrolytes are elaborated, including physical properties, solvation structure, interface chemistry, and safety. Specifically, we focus on the advances and scientific challenges associated with different solvents and the enhancement in their performance after fluorination. Secondly, we discuss the synthetic methods for new fluorinated solvents and their reaction mechanisms in depth. Thirdly, the progress, structure-performance relationship, and applications of fluorinated solvents are reviewed. Subsequently, we provide suggestions on the solvent selection for different battery chemistries. Finally, the existing challenges and further efforts on fluorinated solvents are summarized. The combination of advanced synthesis and characterization approaches with the assistance of machine learning will enable the design of new fluorinated solvents for advanced lithium-based batteries.

Microbial carbon metabolism patterns of microplastic biofilm in the vertical profile of urban rivers.

Microplastics (MPs) can provide a unique niche for microbiota in waters, thus regulating the nutrients and carbon cycling. Following the vertical transport of MPs in waters, the compositions of attached biofilm may be dramatically changed. However, few studies have focused on the related ecological function response, including the carbon metabolism. In this study, we investigated the microbial carbon metabolism patterns of attached biofilm on different MPs in the vertical profile of urban rivers. The results showed that the carbon metabolism capacity of biofilm on the degradable polylactic acid (PLA) MPs was higher than that in the non-degradable polyethylene terephthalate (PET) MPs. In the vertical profile, the carbon metabolism rates of biofilm on two MPs both decreased with water depth, being 0.74 and 0.91 folds in bottom waters of that in surface waters. Specifically, the utilization of polymers, carbohydrate, and amine of PLA biofilm was significantly inhibited in the bottom waters, which were not altered on the PET. Compared with surface waters, the microbial metabolism function index of PLA biofilm was inhibited in deep waters, but elevated in the PET biofilm. In addition, the water quality parameters (e.g., nutrients) in the vertical profile largely shaped carbon metabolism patterns. These findings highlight the distinct carbon metabolism patterns in aquatic environments in the vertical profile, providing new insights into the effects of MPs on global carbon cycle.

Lattice Strained Induced Spin Regulation in Co-N/S Coordination-Framework Enhanced Oxygen Reduction Reaction.

Oxygen reduction reaction (ORR) is the bottleneck of metal-air batteries and fuel cells. Strain regulation can change the geometry and adjust the surface charge distribution of catalysts, which is a powerful strategy to optimize the ORR activity. The introduction of controlled strain to the material is still difficult to achieve. Herein, we present a temperature-pressure-induced strategy to achieve the controlled lattice strain for metal coordination polymers. Through the systematic study of the strain effect on ORR performance, the relationship between geometric and electronic effects is further understood and confirmed. The strained Co-DABDT (DABDT=2,5-diaminobenzene-1,4-dithiol) with 2 % lattice compression exhibits a superior half-wave potential of 0.81 V. Theoretical analysis reveals that the lattice strain changes spin-charge densities around S atoms for Co-DABDT, and then regulates the hydrogen bond interaction with intermediates to promote the ORR catalytic process. This work helps to understand the catalytic mechanism from the atomic level.

The Dependence of Solid Electrolyte Interphase on the Crystal Facet of Current Collector in Li Metal Battery.

The continuous electrolyte decomposition and uncontrolled dendrite growth caused by the unstable solid electrolyte interphase (SEI) have largely hindered the development of Li metal batteries. Here, we demonstrate that tuning the facet of current collector can regulate the composition of SEI and the subsequent Li deposition behavior using single-crystal Cu foils as an ideal platform. The theoretical and experimental studies reveal that the (100) facet of Cu possesses strong adsorption to anions, guiding more anions to participate preferentially in the inner Helmholtz plane and further promoting the formation of the stable inorganic-rich SEI. Consequently, the single-crystal Cu foils with a single [100] orientation (s-Cu(100)) achieve the dendrite-free Li deposition with enhanced Li plating/stripping reversibility. Moreover, the Li anode deposited on s-Cu(100) can stabilize the operation of an Ah-level pouch cell (350 Wh kg-1) with a low negative/positive capacity ratio (~2) and lean electrolyte (2.4 g Ah-1) for 150 cycles. Impressively, this strategy demonstrates universality in a series of electrolytes employed different anions. This work provides new insights into the correlation between the SEI and current collector, opening a universal avenue towards high-performance Li metal batteries.

Active Diluent-Anion Synergy Strategy Regulating Nonflammable Electrolytes for High-Efficiency Li Metal Batteries.

High-energy Li metal batteries (LMBs) consisting of Li metal anodes and high-voltage cathodes are promising candidates of the next generation energy-storage systems owing to their ultrahigh energy density. However, it is still challenging to develop high-voltage nonflammable electrolytes with superior anode and cathode compatibility for LMBs. Here, we propose an active diluent-anion synergy strategy to achieve outstanding compatibility with Li metal anodes and high-voltage cathodes by using 1,2-difluorobenzene (DFB) with high activity for yielding LiF as an active diluent to regulate nonflammable dimethylacetamide (DMAC)-based localized high concentration electrolyte (LHCE-DFB). DFB and bis(fluorosulfonyl)imide (FSI- ) anion cooperate to construct robust LiF-rich solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI), which effectively stabilize DMAC from intrinsic reactions with Li metal anode and enhance the interfacial stability of the Li metal anodes and LiNi0.8 Co0.1 Mn0.1 O2 (NCM811) cathodes. LHCE-DFB enables ultrahigh Coulombic efficiency (98.7 %), dendrite-free, extremely stable and long-term cycling of Li metal anodes in Li || Cu cells and Li || Li cells. The fabricated NCM811 || Li cells with LHCE-DFB display remarkably enhanced long-term cycling stability and excellent rate capability. This work provides a promising active diluent-anion synergy strategy for designing high-voltage electrolytes for high-energy batteries.

Synergistic Regulation of Anode and Cathode Interphases via an Alum Electrolyte Additive for High-performance Aqueous Zinc-Vanadium Batteries.

A zinc (Zn) metal anode paired with a vanadium oxide (VOx) cathode is a promising system for aqueous Zn-ion batteries (AZIBs); however, side reactions proliferating on the Zn anode surface and the infinite dissolution of the VOx cathode destabilise the battery system. Here, we introduce a multi-functional additive into the ZnSO4 (ZS) electrolyte, KAl(SO4)2 (KASO), to synchronise the in-situ construction of the protective layer on the surface of the Zn anode and the VOx cathode. Theoretical calculations and synchrotron radiation have verified that the high-valence Al3+ plays multifunctional roles of competing with Zn2+ for solvation and forming a Zn-Al alloy layer with a homogeneous electric field to mitigate the side reactions and dendrite generation. The Al-containing cathode-electrolyte interface considerably alleviates the irreversible dissolution of the VOx cathode and the accumulation of byproducts. Consequently, the Zn || Zn cell with KASO exhibits an ultra-long cycle of 6000 h at 2 mA cm-2. Importantly, the VOx cathodes (VO2, V2O5 and NH4V4O10) in the ZS-KASO electrolyte showed excellent cycling stability, even at a low negative/positive (N/P) ratio of 2.83 and high mass loading (~16 mg cm-2). This study offers a practical reference for concurrently addressing challenges at the anode and cathode of AZIBs.

Monofluorinated Phosphate with Unique P-F Bond for Nonflammable and Long-Life Lithium-Ion Batteries.

Lithium-ion batteries (LIBs) with conventional carbonate-based electrolytes suffer from safety concerns in large-scale applications. Phosphates feature high flame retardancy but are incompatible with graphite anode due to their inability to form a passivated solid electrolyte interphase (SEI). Herein, we report a monofluorinated co-solvent, diethyl fluoridophosphate (DEFP), featuring a unique P-F bond that allows a trade-off between safety and electrochemical performance in LIBs. The P-F bond in DEFP weakens ion-dipole interactions with Li+ ions, lowering the desolvation barrier, and simultaneously reduces the lowest unoccupied molecular orbital (LUMO) of DEFP, promoting the formation of a robust and inorganic-rich SEI. Additionally, DEFP exhibits improved thermal stability due to both robust SEI and the inherent flame-retardant properties of the P-F bond. Consequently, the optimized DEFP-based electrolyte exhibits improved cyclability and rate capacity in LiNi0.8Co0.1Mn0.1O2 || graphite full cells compared with triethyl phosphate-based electrolytes and commercial carbonate electrolytes. Even at a low E/C ratio of 3.45 g Ah-1, the 1.16 Ah NCM811||Gr pouch cells achieve a high capacity retention of 94.2% after 200 cycles. This work provides a promising approach to decouple phosphate safety and graphite compatibility, paving the way for safer and high-performance lithium-ion batteries.

Asymmetric Solvents Regulated Crystallization-Limited Electrolytes for All-Climate Lithium Metal Batteries.

Electrolytes that can keep liquid state are one of the most important physical metrics to ensure the ions transfer with stable operation of rechargeable lithium-based batteries at a wide temperature window. It is generally accepted that strong polar solvents with high melting points favor the safe operation of batteries above room temperatures but are susceptible to crystallization at low temperatures (≤-40 °C). Here, a crystallization limitation strategy was proposed to handle this issue. We demonstrate that, although the high melting points of ethylene sulfite (ES, -17 °C) and fluoroethylene carbonate (FEC, ≈23 °C), their mixtures can avoid crystallization at low temperatures, which can be attributed to low intermolecular interactions and altered molecular motion dynamics. A suitable ES/FEC ratio (10 % FEC) can balance the bulk and interface transport of ions, enabling LiNi0.8 Mn0.1 Co0.1 O2 ||lithium (NCM811||Li) full cells to deliver excellent temperature resilience and cycling stability over a wide temperature range from -50 °C to +70 °C. More than 66 % of the capacity retention was achieved at -50 °C compared to room temperature. The NCM811||Li pouch cells exhibit high cycling stability under realistic conditions (electrolyte weight to cathode capacity ratio (E/C)≤3.5 g Ah-1 , negative to positive electrode capacity ratio (N/P)≤1.09) at different temperatures.

Surface-Oxygen-Rich Bi@C Nanoparticles for High-Efficiency Electroreduction of CO2 to Formate.

The electrochemical CO2 reduction reaction (CO2RR) is a promising strategy to alleviate excessive CO2 levels in the atmosphere and produce value-added feedstocks and fuels. However, the synthesis of high-efficiency and robust electrocatalysts remains a great challenge. This work reports the green preparation of surface-oxygen-rich carbon-nanorod-supported bismuth nanoparticles (SOR Bi@C NPs) for an efficient CO2RR toward formate. The resultant SOR Bi@C NPs catalyst displays a Faradaic efficiency of more than 91% for formate generation over a wide potential range of 440 mV. Ex situ XPS and XANES and in situ Raman spectroscopy demonstrate that the Bi-O/Bi (110) structure in the pristine SOR Bi@C NPs can remain stable during the CO2RR process. DFT calculations reveal that the Bi-O/Bi (110) structure can facilitate the formation of the *OCHO intermediate. This work provides an approach to the development of high-efficiency Bi-based catalysts for the CO2RR and offers a unique insight into the exploration of advanced electrocatalysts.

Ionic Liquid Electrolyte with Weak Solvating Molecule Regulation for Stable Li Deposition in High-Performance Li-O2 Batteries.

Li-O2 batteries with bis(trifluoromethanesulfonyl)imide-based ionic liquid (TFSI-IL) electrolyte are promising because TFSI-IL can stabilize O2 - to lower charge overpotential. However, slow Li+ transport in TFSI-IL electrolyte causes inferior Li deposition. Here we optimize weak solvating molecule (anisole) to generate anisole-doped ionic aggregate in TFSI-IL electrolyte. Such unique solvation environment can realize not only high Li+ transport parameters but also anion-derived solid electrolyte interface (SEI). Thus, fast Li+ transport is achieved in electrolyte bulk and SEI simultaneously, leading to robust Li deposition with high rate capability (3 mA cm-2 ) and long cycle life (2000 h at 0.2 mA cm-2 ). Moreover, Li-O2 batteries show good cycling stability (a small overpotential increase of 0.16 V after 120 cycles) and high rate capability (1 A g-1 ). This work provides an effective electrolyte design principle to realize stable Li deposition and high-performance Li-O2 batteries.

Quinone Electrodes for Alkali-Acid Hybrid Batteries.

Aqueous batteries are promising candidates for large-scale energy storage but face either limited energy density (lead-acid batteries), cost/resource concerns (Ni-MH batteries), or safety issues due to metal dendrite growth at high current densities (zinc batteries). We report that through designing electrochemical redox couples, quinones as intrinsic dendrite-free and sustainable anode materials demonstrate the theoretical energy density of 374 W h kg-1 coupling with affordable Mn2+/MnO2 redox reactions on the cathode side. Due to the fast K-ion diffusion in the electrolyte, low K-ion desolvation energy at the interface, and fast quinone/phenol reaction, the optimized poly(1,4-anthraquinone) in the KOH electrolyte shows specific capacities of 295 mA h g-1 at 300 C-rate and 225 mA h g-1 at 240 mA cm-2. Further constructed practical aqueous batteries exhibit an output voltage of 2 V in alkali-acid hybrid electrolyte systems with exceptional electrochemical kinetics, which can release/store over 95% of the theoretical capacity in less than 40 s (25 000 mA g-1). The scaled Ah level aqueous battery with the upgradation of interfacial chemistry on the electrode current collector exhibits an overall energy density of 92 W h kg-1, exceeding commercial aqueous lead-acid and Ni-MH batteries. The rapid response, intrinsic dendrite-free existence, and cost efficiency of quinone electrodes provide promising application interests for regulating the output of the electricity grid generated by intermittent solar and wind energy.

Halogenated Zn2+ Solvation Structure for Reversible Zn Metal Batteries.

Rechargeable aqueous Zn metal batteries have become promising candidates for large-scale electrochemical energy storage owing to their high safety and affordable low cost. However, Zn metal anode suffers from dendritic growth and hydrogen evolution reaction (HER), deteriorating the electrochemical performance. Here, we demonstrate that these challenges can be conquered by introducing a halogen ion into the Zn2+ solvation structure. By designing an electrolyte composed of zinc acetate and ammonium halide, the electron-donating anion I- can coordinate with Zn2+ and transform the traditional Zn(H2O)62+ to ZnI(H2O)5+, in which I- could transfer electrons into H2O and thus suppress HER. The dynamic electrostatic shielding layer formed by concomitant NH4+ can restrict the dendritic growth. As a result, the halogenated electrolyte achieves a high initial coulombic efficiency (CE) of 99.3% in the Zn plating/stripping process and remains at an average of ∼99.8% with uniform Zn deposition. Moreover, Zn-I batteries are constructed by using dissociative I- as the cathode and carbon felt-polyaniline as the conductive and adsorptive layer, exhibiting an average CE of 98.6% without capacity decay after 300 cycles. This work provides insights into the halogenated Zn2+ solvation structure and offers a general electrolyte design strategy for achieving a highly reversible Zn metal anode and batteries.

Designing Quinone-Based Anodes with Rapid Kinetics for Rechargeable Proton Batteries.

Quinone compounds, which are capable of accommodating proton (H+ ), are emerging electrodes in aqueous batteries. However, the storage mechanism of proton in quinone compounds is less known and the energy/power density of quinone-based proton battery is still limited. Here we design a series of quinone anodes and study their electrochemical properties in acidic electrolyte, in which tetramethylquinone (TMBQ) delivers a high capacity of 300 mAh g-1 with an extremely low polarization of 20 mV at 1 C, and maintains over 50 % theoretical capacity in less than 16 seconds. The fast kinetics of TMBQ is attributed to the continuous H+ migration channel, high H+ diffusion coefficient (10-6  cm2 s-1 ), and low H+ migration energy barrier (0.26 eV). When coupling with MnO2 cathode, the battery shows a long lifespan of 4000 cycles with a capacity retention of 77 % at 5 C. This study reveals the proton transport in quinone-electrodes and offers new insights to design advanced aqueous batteries.