HAOBO DONG

Zinc-ion batteries (ZIBs) have emerged as a promising candidate due to the abundance, low cost and high energy density. However, the performance of ZIBs needs to be improved to meet the practical requirements of energy storage systems. This work probes the efficacy of co-intercalation as a strategy for enhancing the electrochemical performance of ZIBs through the fabrication of sodium and copper co-intercalated birnessite manganese oxide (NCMO) cathodes. The results show that the co-intercalation of sodium and copper ions catalyzes the activation of copper cations on the surface Mn2+/Mn4+ redox pair, leading to improved specific capacity and cycling stability. The NCMO cathode exhibits a remarkable specific capacity of 576 mAh g-1 after 100 cycles at a low loading of around ~1 mg cm-2 and a high areal capacity of 2.10 mAh cm-2 at a high loading of ~10.9 mg cm-2. The mechanism of copper ions to …

The design and synthesis of manganese oxide-based materials with high-rate performance and long cycle life is a major challenge for aqueous zinc-ion batteries (AZIBs). This research reports the presence of a synergistic collaboration between vacancies, lattice water and nickel ions on enhancing the hydrated protons hopping via the Grotthuss mechanism for high-performance zinc ion batteries. The Grotthuss mechanism allows for the efficient transfer of a proton charge without the actual movement of the molecule over long distances, resulting in high ionic conductivity. NiMn3O7·3H2O achieves a capacity of 318 mA h g−1 under 200 mA g−1 and 121 mA h g−1 under 5 A g−1 with a retention of 91% after 4000 cycles. The relationship between the remarkable performance and Grotthuss topochemistry is investigated using techniques including synchrotron X-ray absorption spectroscopy and density functional …

The paper discusses the progress and commercialization of binders for energy storage applications, such as batteries. It explains the role of binders in holding together active materials and current collectors, and highlights the challenges associated with conventional organic solvents in binders. The potential of aqueous binders is introduced as a cost-effective and environmentally friendly alternative. The advantages and limitations of different types of binders are discussed, and the importance of binder selection for optimal battery performance is emphasized. The current state of commercialization of binders is reviewed, and the need for collaboration between researchers, manufacturers, and policymakers to develop and promote environmentally friendly and cost-effective binders is emphasized. The paper concludes by outlining future directions for research and development to further improve the performance and commercialization of binders, while addressing limitations such as lack of standardization, high cost, and long-term stability and reliability.

This research introduces a chemistry-agnostic approach to achieve rapid and degradation-free battery charging via ultrasonic agitation. An ultrasonic device operating in the megahertz range was used to stimulate electrolyte flow from outside the cell. The acoustic streaming effect accelerates ion transport from the bulk electrolyte to the electrode surface and suppresses the formation of an ion depletion zone. An experimental setup was used to optically observe the formation of dendrites when the current imposed across two zinc electrodes exceeded the limiting current. Beyond this limit, diffusion alone cannot provide sufficient ions, resulting in an ion depletion zone. It was subsequently shown that dendrite formation was reduced by over 98% when 15x the limiting current was forced across the electrodes and acoustic stimulation was delivered. Furthermore, it was shown that compared to the scenario without …

The in‐depth understanding of the composition‐property‐performance relationship of solid electrolyte interphase (SEI) is the basis of developing a reliable SEI to stablize the Zn anode‐electrolyte interface, but it remains unclear in rechargeable aqueous zinc ion batteries. Herein, a well‐designed electrolyte based on 2M Zn(CF3SO3)2‐0.2M acrylamide‐0.2M ZnSO4 is proposed. A robust polymer (polyacrylamide)‐inorganic (Zn4SO4(OH)6.xH2O) hybrid SEI is in‐situ constructed on Zn anodes through controllable polymerization of acrylamide and coprecipitation of SO42‐ with Zn2+ and OH‐. For the first time, the underlying SEI composition‐property‐performance relationship is systematically investigated and correlated. The results showed that the polymer‐inorganic hybrid SEI, which integrates the high modulus of the inorganic component with the high toughness of the polymer ingredient, can realize high …

A stable cathode–electrolyte interface (CEI) is crucial for aqueous zinc‐ion batteries (AZIBs), but it is less investigated. Commercial binder poly(vinylidene fluoride) (PVDF) is widely used without scrutinizing its suitability and cathode‐electrolyte interface (CEI) in AZIBs. A water‐soluble binder is developed that facilitated the in situ formation of a CEI protecting layer tuning the interfacial morphology. By combining a polysaccharide sodium alginate (SA) with a hydrophobic polytetrafluoroethylene (PTFE), the surface morphology, and charge storage kinetics can be confined from diffusion‐dominated to capacitance‐controlled processes. The underpinning mechanism investigates experimentally in both kinetic and thermodynamic perspectives demonstrate that the COO− from SA acts as an anionic polyelectrolyte facilitating the adsorption of Zn2+; meanwhile fluoride atoms on PTFE backbone provide hydrophobicity to …

The paper discusses the challenges associated with the performance of zinc‐ion batteries (ZIBs), such as side reactions that lead to reduced capacity and lifespan. The strategies for mitigating side reactions in ZIBs, including additives, electrolyte‐electrode interface modification, and electrolyte composition optimization, are explored. Combinations of these approaches may be necessary to achieve the best performance for ZIBs. However, continued research is needed to improve the commercial viability of ZIBs. Areas of research requiring attention include the understanding of the mechanisms behind side reactions in ZIBs and the development of cost‐effective and scalable manufacturing processes for ZIBs with available electrolyte. By developing effective strategies for mitigating side reactions, researchers can improve the efficiency and lifespan of ZIBs, making them more competitive with lithium‐ion batteries in …

High-voltage cathodes with high power and stable cyclability are needed for high-performance sodium-ion batteries. However, the low kinetics and inferior capacity retention from structural instability impede the development of Mn-rich phosphate cathodes. Here, we propose light-weight fluorine (F) doping strategy to decrease the energy gap to 0.22 eV from 1.52 eV and trigger a “Mn-locking” effect—to strengthen the adjacent chemical bonding around Mn as confirmed by density functional theory calculations, which ensure the optimized Mn ligand framework, suppressed Mn dissolution, improved structural stability and enhanced electronic conductivity. The combination of in situ and ex situ techniques determine that the F dopant has no influence on the Na+ storage mechanisms. As a result, an outstanding rate performance up to 40C and an improved cycling stability (1000 cycles at 20C) are achieved. This work …

Due to their potential for high energy density, low cost, and environmental sustainability, zinc-ion batteries (ZIBs) have emerged as a promising energy storage technology. The performance, safety, and overall efficiency of ZIBs are significantly impacted by the properties of the electrolyte, such as ionic conductivity, electrochemical stability window, viscosity, and compatibility with other battery components. The use of ionic liquids (ILs) in ZIBs has gained extensive attention in recent years due to their desirable properties, such as high thermal stability, low volatility, wide electrochemical window, and tunable physicochemical properties. Therefore, this paper provides a bibliometric analysis of recent advances in the use of ILs as electrolytes in ZIBs. Current research trends, authorship patterns, and publications of ILs in ZIBs are analyzed. Our review reveals a growing interest in the use of ILs as electrolytes in ZIBs, and …

Platinum (Pt) is regarded as a promising electrocatalyst for hydrogen evolution reaction (HER). However, its application in an alkaline medium is limited by the activation energy of water dissociation, diffusion of H+, and desorption of H*. Moreover, the formation of effective structures with a low Pt usage amount is still a challenge. Herein, guided by the simulation discovery that the edge effect can boost local electric field (LEF) of the electrocatalysts for faster proton diffusion, platinum nanocrystals on the edge of transition metal phosphide nanosheets are fabricated. The unique heterostructure with ultralow Pt amount delivered an outstanding HER performance in an alkaline medium with a small overpotential of 44.5 mV and excellent stability for 80 h at the current density of −10 mA cm−2. The mass activity of as‐prepared electrocatalyst is 2.77 A mg−1Pt, which is 15 times higher than that of commercial Pt/C …

Aqueous zinc (Zn) batteries hold great promise for large-scale energy storage by virtue of the high sustainability, low cost of Zn resources, high safety and low environmental impact. However, severe side reactions including Zn dendrite growth at the Zn surface hinder their practical application.“Water-in-salt” and organic/aqueous hybrid electrolytes address these problems but compromise the intrinsic merits of high ionic conductivity, superior safety, low cost and good sustainability. Herein, methylurea (MU) which has hydrogen (H) bond donor/acceptor properties is examined as a multifunctional electrolyte additive to boost the Zn anode reversibility without compromising the above advantages of aqueous electrolytes. Systematic experimental and theoretical analyses confirm that MU molecules alter the H-bonding network and reconstruct Zn 2+ solvation sheath; furthermore, the desolvation process can be facilitated with lower energy barriers. Besides, MU additives tend to be absorbed on the Zn surface to build a water-poor electrical double layer and can in-situ form a robust solid electrolyte interphase layer that protects the Zn anode. The Zn (002) plane is predominately deposited and can also be guided by MU. Consequently, the lifespan of the Zn|| Zn cell using MU can maintain over 3000 h and the average Coulombic efficiency of the Zn|| Cu cell reaches 99.7% throughout 1800 cycles. Additionally, our strategy can be applied in full cells with boosted performances for MnO 2, activated carbon and conversion-type I 2 (capacity retention: 93.2% throughout 7500 cycles) cathodes under practical electrode ratios.

Although their cost-effectiveness and intrinsic safety, aqueous zinc-ion batteries suffer from notorious side reactions including hydrogen evolution reaction, Zn corrosion and passivation, and Zn dendrite formation on the anode. Despite numerous strategies to alleviate these side reactions have been demonstrated, they can only provide limited performance improvement from a single aspect. Herein, a triple-functional additive with trace amounts, ammonium hydroxide, was demonstrated to comprehensively protect zinc anodes. The results show that the shift of electrolyte pH from 4.1 to 5.2 lowers the HER potential and encourages the in situ formation of a uniform ZHS-based solid electrolyte interphase on Zn anodes. Moreover, cationic NH4+ can preferentially adsorb on the Zn anode surface to shield the “tip effect” and homogenize the electric field. Benefitting from this comprehensive protection, dendrite-free Zn …

Zinc‐ion batteries (ZIBs), which are inexpensive and environmentally friendly, have a lot of potential for use in grid‐scale energy storage systems, but their use is constrained by the availability of suitable cathode materials. MnO2‐based cathodes are emerging as a promising contenders, due to the great availability and safety, as well as the device's stable output voltage platform (1.5 V). Improving the slow kinetics of MnO2‐based cathodes caused by low electrical conductivity and mass diffusion rate is a challenge for their future use in next‐generation rapid charging devices. Herein, the aforementioned challenges are overcome by proposing a sodium‐intercalated manganese oxide (NMO) with 3D varying thinness carbon nanotubes (VTCNTs) networks as appropriate free‐standing, binder‐free cathodes (NMO/VTCNTs) without any heat treatment. A network construction strategy based on CNTs of different …

Zn‐based hybrid supercapacitors (ZHSCs) have received increasing attention in recent research, due to their high electrochemical performance and low cost. Herein, a composite cathode is developed based on polyaniline (PANI) and cobalt hexacyanoferrate (CoHCF), exhibiting excellent electrochemical performance. The results showed that PANI is coated on CoHCF, thereby enhancing the electrical conductivity and Zn2+ transport kinetics. As a result, the as‐prepared materials demonstrate remarkable specific capacitance (741.7 F g−1 at 5 mV s−1), good cycling durability (86.15% capacitance retention over 5000 cycles at 10 A g−1), high peak energy density (312 Wh kg−1 at 500 W kg−1), and superior power density (75 294 W kg−1 at 25 Wh kg−1). The excellent electrochemical performance confirms that PANI–CoHCF composites are promising cathode candidates for ZHSCs in practical …

The electrochemical effect of isotope (EEI) of water is introduced in the Zn‐ion batteries (ZIBs) electrolyte to deal with the challenge of severe side reactions and massive gas production. Due to the low diffusion and strong coordination of ions in D2O, the possibility of side reactions is decreased, resulting in a broader electrochemically stable potential window, less pH change, and less zinc hydroxide sulfate (ZHS) generation during cycling. Moreover, we demonstrate that D2O eliminates the different ZHS phases generated by the change of bound water during cycling because of the consistently low local ion and molecule concentration, resulting in a stable interface between the electrode and electrolyte. The full cells with D2O‐based electrolyte demonstrated more stable cycling performance which displayed ∼100 % reversible efficiencies after 1,000 cycles with a wide voltage window of 0.8–2.0 V and 3,000 …

For zinc‐ion batteries (ZIBs), the non‐uniform Zn plating/stripping results in a high polarization and low Coulombic efficiency (CE), hindering the large‐scale application of ZIBs. Here, inspired by biomass seaweed plants, an anionic polyelectrolyte alginate acid (SA) was used to initiate the in situ formation of the high‐performance solid electrolyte interphase (SEI) layer on the Zn anode. Attribute to the anionic groups of −COO−, the affinity of Zn2+ ions to alginate acid induces a well‐aligned accelerating channel for uniform plating. This SEI regulates the desolvation structure of Zn2+ and facilitates the formation of compact Zn (002) crystal planes. Even under high depth of discharge conditions (DOD), the SA‐coated Zn anode still maintains a stable Zn stripping/plating behavior with a low potential difference (0.114 V). According to the classical nucleation theory, the nucleation energy for SA‐coated Zn is 97 % less …

A conventional aqueous electrolyte is a crucial component of zinc-ion batteries providing an ion conductive medium. However, the monofunction of a liquid electrolyte cannot bear any external load. With regard to applications in electric vehicles and stationary energy storage devices, complicated battery packing materials are required to improve the mechanical properties, resulting in reduced energy or power densities from the perspective of the entire device. In this work, an electrolyte suspension combining both fluid-like and solid-like performances was developed for rechargeable zinc-ion batteries. Cornstarch water suspension is utilized in the electrolyte design forming a shear-thickening electrolyte with impact resistance ability. The formed electrolyte becomes rigid at a high shear rate. In other words, under a sudden impact, a battery with this shear-thickening electrolyte could offer additional load bearing …

Aqueous zinc-ion batteries (AZIBs), deemed as potential candidates for gird/off-grid stationary energy storage, have attracted intensive attention over the last five years because of the advantages in the high volumetric capacity (5855 mAh cm−3) of Zn metal, robustness in aqueous electrolytes and relatively low cost. However, the sluggish Zn2+ diffusion mechanism results in cathode dissolution and even dendrite formation restricting the stability of the battery performance. Polymer electrolytes are of interests owing to their enhanced internal structure and less absorbed water molecules. Therefore, this thesis has developed strategies for stabilising the cathode active materials using polymer electrolytes. With an intensive understanding of hydrogel and solid polymer electrolytes, the electrode-electrolyte interface has been notified as the most critical factor for zinc-ion battery. A universal strategy in interfacial engineering stabilising cathode with the merit of polymer electrolytes has been proposed. Step-by-step investigations are carried out firstly in developing a cathode-stabilised hydrogel electrolyte, then unveiling the interface ageing issue of the polymer electrolytes, and eventually, an innovative interfacial binder design with the emphasis on cathode stabilisation has been developed. Physiochemical and electrochemical characterisations have been performed to unveil the kinetics in detail; moreover, ex-situ materials characterisations and density functional theory (DFT) simulations were also adopted to elucidate specific characteristics of as-prepared polymer electrolytes and interface engineering.

Dendrites form on the surface of metal electrodes as a battery undergoes repeated charging and discharging. The formation of dendrites not only affects the electrochemical performances of a battery but may also cause internal short-circuiting and thermal runaway events. Hence, there is a clear need to understand the formation mechanisms and growth kinetics of dendrites. Currently available technologies such as (in-situ) X-ray computed tomography and scanning electron microscopy can be used in a laboratory environment to study dendrite formation. However, they are often prohibitively expensive or unsuitable for long-term, large-scale, and in-operando monitoring.In this study we present an ultrasound-based technique which is cheap, with potential to scale up, and suitable in both laboratory and industrial environments. Different from conventional ultrasonic approaches which excite ultrasonic waves that …

Metal dendrites can form on the electrode surface when a battery is repeatedly charged and discharged, this often results in reduced electrochemical performance and occasionally even internal short-circuiting. Hence, intensive research to study the underlying growth kinetics of dendrites in batteries has been initiated. However, existing technologies such as scanning electron microscopy and x-ray computed tomography are prohibitively expensive for in-operando monitoring. Recently, ultrasound-based techniques have become a promising alternative method for monitoring the health and status of battery cells. However, most of the reported ultrasonic methods utilise bulk waves which propagate through a laminated structure of cathode, anode, and electrolyte. In this study we use miniature transducers to excite fundamental shear-horizontal mode (SH0*) guided ultrasonic waves that propagate along an individual …

Vanadium bronzes have been well-demonstrated as promising cathode materials for aqueous zinc-ion batteries. However, conventional single-ion pre-intercalated V2O5 nearly reached its energy/power ceiling due to the nature of micro/electronic structures and unfavourable phase transition during Zn2+ storage processes. Here, a simple and universal in-situ anodic oxidation method of quasi-layered CaV4O9 in a tailored electrolyte was developed to introduce dual ions (Ca2+ and Zn2+) into bilayer δ-V2O5 frameworks forming crystallographic ultra-thin vanadium bronzes, Ca0.12Zn0.12V2O5·nH2O. The materials deliver transcendental maximum energy and power densities of 366 W h kg−1 (478 mA h g−1 @ 0.2 A g−1) and 6627 W kg−1 (245 mA h g−1 @ 10 A g−1), respectively, and the long cycling stability with a high specific capacity up to 205 mA h g−1 after 3000 cycles at 10 A g−1. The synergistic …

Aqueous zinc-ion batteries are promising alternatives to lithium-ion batteries for grid-scale energy storage. However, the practical application of AZIBs is challenged by side reactions and unsatisfactory performance. Electrolyte additives are reported that can inhibit side reactions on the Zn anode and enlarge the working potential window of aqueous electrolytes. Here we propose that trace amounts of perfluorooctanoic acid (PFOA) can facilitate long-term reversible Zn deposition in AZIBs due to perfluorinated n-octyl chains ordered orientation adsorbing on the electrode surface. Benefitting from its intrinsic surfactant properties, PFOA additives can reduce the surface tension of electrolytes and improve the wettability of electrolytes on the electrode. Symmetric Zn cells survived up to 2200 hours owing to the self-adjusting absorption layer. The molecular dynamics results show that the as-formed electronegative …

Zinc-ion batteries (ZIBs) have attracted intensive attention over the last five years due to the high volumetric capacity (5855 mAh cm−3) of zinc metals and the robust fabrication process under ambient conditions. With the development of ZIBs, flexible zinc-ion batteries (FZIBs) are deemed as potential candidates for powering flexible devices, especially wearable and implantable medical devices. Different from flexible Li-ion, Na-ion, and K-ion batteries, polymer/hydrogel electrolytes are widely utilized in FZIBs providing flexibility and biocompatibility. Currently, polymer electrolytes can be categorized into three clusters: solid polymer electrolytes (SPEs); hydrogel polymer electrolytes (HPEs), and hybrid polymer electrolytes (HBPEs). With the application of polymer electrolytes, electrochemical properties can be enhanced, and additional functionalities can be provided. Although FZIBs are still in their infancy, substantial …

The formation of dendrite affects the cycling life of a battery and lead to malfunctions such as internal short-circuiting and thermal runaway events. However, existing methods to observe dendrite formation, such as X-ray computed tomography and scanning electron microscopy are either prohibitively complicated or unsuitable for long-term, in-situ monitoring. In this study we present a method which uses the fundamental shear-horizontal mode (SH0*) guided ultrasonic waves to independently monitor the status of the electrodes in a symmetric aqueous zinc-ion battery. Experimental measurements show that the velocity and attenuation of the ultrasonic wave on the opposing electrodes vary in the opposite senses during the cycling. While the velocity and attenuation changes can be partially reversed, a monotonic drift can also be observed with increasing number of cycles. Coupled with optical microscopy, the …

Owing to the development of aqueous rechargeable zinc‐ion batteries (ZIBs), flexible ZIBs are deemed as potential candidates to power wearable electronics. ZIBs with solid‐state polymer electrolytes can not only maintain additional load‐bearing properties, but exhibit enhanced electrochemical properties by preventing dendrite formation and inhibiting cathode dissolution. Substantial efforts have been applied to polymer electrolytes by developing solid polymer electrolytes, hydrogel polymer electrolytes, and hybrid polymer electrolytes; however, the research of polymer electrolytes for ZIBs is still immature. Herein, the recent progress in polymer electrolytes is summarized by category for flexible ZIBs, especially hydrogel electrolytes, including their synthesis and characterization. Aiming to provide an insight from lab research to commercialization, the relevant challenges, device configurations, and life cycle …

The primary issue faced by MnO2 cathode materials for aqueous Zn-ion batteries (AZIBs) is the occurrence of structural transformations during cycling, resulting in unstable capacity output. Pre-intercalating closely bonded ions into the MnO2 structures has been demonstrated as an effective approach to combat this. However, mechanisms of the pre-intercalation remain unclear. Herein, two distinct δ-MnO2 (K0.28MnO2·0.1H2O and K0.21MnO2·0.1H2O) are prepared with varying amounts of pre-intercalated K+ and applied as cathodes for AZIBs. The as-prepared K0.28MnO2·0.1H2O cathodes exhibit relatively high specific capacity (300 mA h g−1 at 100 mA g−1), satisfactory rate performance (35% capacity recovery at 5 A g−1) and competent cyclability (ca. 95% capacity retention after 1000 cycles at 2 A g−1), while inferior cyclability and rate performance are observed in K0.21MnO2·0.1H2O. A stable δ-MnO2 phase …

Aqueous zinc-ion batteries (AZIBs) have the potential to be utilized in a grid-scale energy storage system owing to their high energy density and cost-effective properties. However, the dissolution of cathode materials and the irreversible extraction of preintercalated metal ions in the electrode materials restrict the stability of AZIBs. Herein, a cathode-stabilized ZIB strategy is reported based on a natural biomass polymer sodium alginate as the electrolyte coupling with a Na+ preintercalated δ-Na0.65Mn2O4·1.31H2O cathode. The dissociated Na+ in alginate after gelation directly stabilizes the cathodes by preventing the collapse of layered structures during charge processes. The as-fabricated ZIBs deliver a high capacity of 305 mA h g–1 at 0.1 A g–1, 10% higher than the ZIBs with an aqueous electrolyte. Further, the hybrid polymer electrolyte possessed an excellent Coulombic efficiency above 99% and a capacity …

Cost‐effective and environment‐friendly aqueous zinc‐ion batteries (AZIBs) exhibit tremendous potential for application in grid‐scale energy storage systems but are limited by suitable cathode materials. Hydrated vanadium bronzes have gained significant attention for AZIBs and can be produced with a range of different pre‐intercalated ions, allowing their properties to be optimized. However, gaining a detailed understanding of the energy storage mechanisms within these cathode materials remains a great challenge due to their complex crystallographic frameworks, limiting rational design from the perspective of enhanced Zn2+ diffusion over multiple length scales. Herein, a new class of hydrated porous δ‐Ni0.25V2O5.nH2O nanoribbons for use as an AZIB cathode is reported. The cathode delivers reversibility showing 402 mAh g−1 at 0.2 A g−1 and a capacity retention of 98% over 1200 cycles at 5 A g−1. A …

Polymer electrolytes have been extensively applied in zinc-ion batteries, especially those based on hydrogels; however, the densification of the hydrogel electrolytes during cycling affects the durability, resulting in capacity attenuation. It is revealed in this work that the surface electrical resistance of hydrogels is particularly affected by the aging effect. Hence, an adhesive bonding solid polymer electrolyte (ABSPE) for zinc-ion batteries was developed exhibiting significantly enhanced anti-aging properties, where the surface resistance remains constant for over 200 hours, twice that of conventional hydrogel electrolytes. For the hydrogel electrolyte, the surface resistance only remains constant for less than 100 hours which is half of the time achieved by the ABSPE. The ionic conductivity increases with plasticizer loading, reaching 3.77 × 10−4 S cm−1. The kinetic mechanism probed in this work revealed a diffusion …