Aqueous Battery System Research Articles

3D Spiral Zinc Electrode for Rechargeable Aqueous Zinc-Air Battery

Zinc metal has emerged as seeded anode material in the field of high-efficiency aqueous metal-air battery system due to the advantages of abundant reserves, strong reversibility and high capacity. Unfortunately, the conventional zinc electrodes commonly adopt a flat structure, and the dendrite accumulation and corrosion during the cycle process lead to sub-optimal efficiency and performance. Herein, the zinc electrode is designed as a three-dimensional (3D) spiral structure to improve the utilization efficiency of zinc and the quality of the battery. Compared with the zinc plate, the 3D spiral zinc electrode can shorten the movement distance of the particles in space and the operation period in time, increase the specific surface area of the reaction, reduce the resistance of mass and charge transfer, and achieve the effect of optimizing the performance of the battery system. The results show that the aqueous zinc-air battery made of 3D spiral zinc electrode exhibits better charge-discharge characteristics, higher power density and narrower voltage windows. This study demonstrates a zinc anode with simple feasibility properties and a special structure, aiming to provide a new research direction and innovation strategy for the development of high-performance rechargeable zinc-air battery systems.

Strategies for design and modification of electrode materials in novel aqueous ammonium ion battery

Aqueous ammonium ion battery, as a new candidate aqueous energy storage system, attracts much attention on account of the unique characteristics including lightest molar mass and the smallest hydrated ionic size of ammonium ion as charge carriers. In the assembled aqueous system, the hydrated vanadium oxide of (NH4)2V6O16∙1.5 H2O (NHVOw) with nanorod morphology as cathode is successfully synthesized and further modified by loading carbon on the surface to obtain the composite (NH4)2V6O16∙1.5 H2O/Carbon (NHVOw/C), which exhibits more excellent electrochemical performance due to the enlarged layered structure and high conductivity from carbon material. Meanwhile, the 1,4,5,8-naphthalenetetracarboxylic dianhydride-derived polyimide abbreviated as PNTCDA with multiple carbonyl groups as anode is synthesized and exhibits outstanding rate capability. Finally, this aqueous ammonium ion full battery is firstly assembled by NHVOw/C as cathode and PNTCDA as anode in NH4Cl electrolyte, which fully demonstrates the feasibility of ammonium ion energy storage and provides a new idea for aqueous battery systems.

A Universal Strategy Toward Low‐Cost Aqueous Sulfur–Iodine Batteries

AbstractRechargeable aqueous batteries with non‐toxic and non‐flammable features are promising candidates for large‐scale energy storage. However, their practical applications are impeded by the insufficient electrochemical stability windows of aqueous electrolytes and intrinsic drawbacks of current electrodes. Herein, an aqueous sulfur–iodine chemistry that can be deployed in aqueous battery systems by employing water‐in‐bisalt (WiBS) electrolyte, sulfur composite anode, and iodine composite cathode is demonstrated. The freestanding iodine/carbon cloth cathode and halide‐containing WiBS electrolyte can support the continuous I+/I0 reaction by forming interhalogen. Meanwhile, the highly‐concentrated electrolyte and inorganic‐based solid electrolyte interphase can effectively suppress the dissolution/diffusion of polysulfides, thus realizing S/Sx2− conversion reactions on the anode. Therefore, the as‐assembled aqueous sulfur–iodine batteries based on S/Sx2− and I+/I0 redox couples can deliver a high energy density of 158.7 Wh kg−1 with a considerable cycling performance and safety. Furthermore, this chemistry can be further extended to multivalent ion‐based battery systems. As demonstration models, Ca‐based and Al‐based aqueous sulfur–iodine batteries are also fabricated, which provide a new avenue towards the development of aqueous batteries for low‐cost and highly safe energy storage.

Ultrastable Cu2+ Intercalation Chemistry Based on a Niobium Sulfide Nanosheet Cathode for Advanced Aqueous Storage Devices

Exploring stable and durable cathodes for cost-effective reversible aqueous batteries is highly desirable for grid-scale energy storage applications, but significant challenges remain. Herein, we disclosed an ultrastable Cu2+ intercalation chemistry in mass-produced exfoliated NbS2 nanosheets to build ultralong lifespan aqueous batteries with cost advantages. Anisotropic interplanar expansion of NbS2 lattices balanced dynamic Cu2+ incorporation and the highly reversible redox reaction of Nb4+/Nb(4-δ)+ couple were illuminated by operando synchrotron X-ray diffraction and energy dispersive X-ray absorption spectroscopy, affording an extraordinary capacity of approximately 317 mAh g-1 at 1 A g-1 and a good stability of 92.2% capacity retention after 40000 cycles at 10 A g-1. Impressively, a budget NbS2||Fe hybrid ion cell involving an aqueous electrolyte/Fe-metal anode is established and provides a reliable energy supply of 225.4 Wh kg-1 at 750 W kg-1, providing insights for building advanced aqueous battery systems for large-scale applications.

Efficient electrochemical performance of MnO2 nanowires interknitted vanadium oxide intercalated nanoporous carbon network as cathode for aqueous zinc ion battery

Rechargeable aqueous Zn-ion batteries (AZIBs) have emerged as promising large-scale energy storage devices because of their low cost and good safety characteristics. Vanadium oxide-based materials have been actively studied as future cathode materials for AZIBs, benefiting from their suitable voltage and high specific capacity. However, poor rate performance and capacity deterioration due to the instability of their oxides is still a hurdle in their commercialization. Herein, we attempted to test a methodology involving the carbonization of V-MIL-101 to prepare a composite material consisting of vanadium oxide nanoparticles embedded within the nanoporous carbon network, which remarkably enhances the electrochemical performance of the material as a cathode in an aqueous Zn-ion battery system. The manganese oxide loading further stabilized the composite material, which improved the cathode material's rate capability in aq. zinc ion battery cathode. The cathode material MnO2@NVC composite exhibited the capacity of 299 mAhg−1 at 0.1C rate for 100 cycles benefitting from the synergistic effect of the high conductivity of Vanadium oxide nanoparticles and suitable voltage of MnO2. The materials showed superior capacity retention and better cycling performance than unmodified vanadium oxide nanoparticles on carbon substrate as cathode material. The comparative morphological and electrochemical studies confirm the improved performance, which suggests that the vanadium oxide nanoparticles anchored on a high surface area carbon network intertwined with manganese oxide nanowires provide enhanced conductivity.

Environmentally Friendly and Flexible Aqueous Zinc Ion Batteries Using an Organic Anode and Activated Carbon as the Cathode

We report an outstanding rate capability of a synthesized polymer, poly(3,4,9,10-perylentetracarboxylic diimide) (PPTCDI), as an anode with activated carbon (AC) as a cathode. The cell PPTCDI||AC shows the highest energy density of 174.3 Wh kg–1. The electrode PPTCDI provides a superior rate capability of 199.1 mAh g–1 at a 50 mA g–1 current density. A flexible zinc-ion battery is assembled for the first time using AC and PPTCDI in an aqueous ZnSO4 electrolyte, exhibiting a capacity retention of 95% after 5000 cycles. This work ascertains the feasibility of Zn-ion energy storage and provides a new idea for aqueous battery systems.

Vanadium-Based Cathodic Materials of Aqueous Zn-Ion Battery for Superior-Performance with Prolonged-Life Cycle.

Aqueous Zn-ion battery systems (AZIBs) have emerged as the most dependable solution, as demonstrated by successful systematic growth over the past few years. Cost effectivity, high performance and power density with prolonged life cycle are some major reason of the recent progress in AZIBs. Development of vanadium-based cathodic materials for AZIBs has appeared widely. This review contains a brief display of the basic facts and history of AZIBs. An insight section on zinc storage mechanism ramifications is given. A detailed discussion is conducted on features of high-performance and long life-time cathodes. Such features include design, modifications, electrochemical and cyclic performance, along with stability and zinc storage pathway of vanadium based cathodes from 2018 to 2022. Finally, this review outlines obstacles and opportunities with encouragement for gathering a strong conviction for future advancement in vanadium-based cathodes for AZIBs.

An anode-free aqueous hybrid batteries enabled by in-situ Cu/Sn/Zn alloy formation on pure Cu substrate

Zn-based rechargeable aqueous battery attracts attention due to its simplicity and benignity. Here, we propose an anode-free aqueous hybrid system with 4 M ZnSO4 and 2 M Li2SO4 in 10% DME. Since the electrolyte is the only source of Zn, the capacity ratio between Zn salts and the cathode is also evaluated to achieve a suitable formulation of the electrolyte composition. To improve the Zn nucleation and densify the deposition, we include an additive SnBr2 to initiate the in-situ formation of Cu/Sn/Zn alloy on the surface of the Cu current collector. The effects of the SnBr2 additive on the Zn deposition, stripping, and the Cu/Sn/Zn alloy formation was investigated and characterized. SEM, cross-sectional analysis by Focused ion beam (FIB), and in-situ transmission X-ray microscope (TXM) all confirm the more uniform and dense deposition of Zn on Cu under the assistance of SnBr2. The anode-free hybrid aqueous Cu||LFP full cell achieves 99.1% average coulombic efficiency with relatively good capacity retention (35.2%) after 100 cycles by adding SnBr2 in the hybrid electrolyte with an optimized electrolyte/cathode capacity ratio of 9.45. The proposed anode-free approach is hoped to help the sustainable development of an aqueous battery system with high energy density and environmental benignity.

Phase-Transformation-Activated MnCO3 as Cathode Material of Aqueous Zinc-Ion Batteries

The intrinsic high safety of rechargeable aqueous batteries makes them particularly advantageous in the field of large-scale energy storage. Among them, rechargeable Zn–Mn batteries with high energy density, low cost, high discharge voltage, and nontoxicity have been considered as one of the most promising aqueous battery systems. However, exiting research on manganese-based cathode materials mainly focuses on diverse manganese oxides analogs, while reports on other promising manganese-based analogs with high performance are still limited. Herein, we report a MnCO3 cathode material, which can be manufactured on a large scale by a facile coprecipitation method. Interestingly, the MnCO3 can spontaneously be converted into MnO2 material during the charging process. The Zn–MnCO3 battery delivers a highly specific capacity (280 mAh g−1) even at the high current density of 50 mA g−1. It is also noteworthy that the battery with a high loading mass (7.2 mg cm−2) exhibits good reversibility of charge–discharge for 2000 cycles, showing a competitive cycling stability in aqueous systems.

Electrochemical Study of Polymorphic MnO2 in Rechargeable Aqueous Zinc Batteries

Manganese dioxide is regarded as a promising energy functional material due to its open tunnel structure with enormous applications in energy storage and catalysis. In this paper, α-MnO2 with a 2 × 2 tunnel structure and β-MnO2 with a 1 × 1 tunnel structure were hydrothermally synthesized, which possess characteristic tunnel structures formed by the interconnected unit structure of [MnO6] octahedrons. With regards to their different tunnel dimensions, the specific mechanism of ion intercalation in these two phases and the effect on their performance as aqueous Zn-MnO2 battery cathodes are explored and compared. Comprehensive analyses illustrate that both α-MnO2 and β-MnO2 provide decent capacity in the aqueous battery system, but their intrinsic stability is poor due to the structural instability upon cycling. At the same time, experiments show that α-MnO2 has a better rate performance than β-MnO2 under larger currents, thus implying that the former has a broader application in this aqueous battery system.

Dilute Hybrid Electrolyte for Low-Temperature Aqueous Sodium-Ion Batteries.

A hybrid electrolyte based on low-concentration sodium nitrate with glycerol as an additive was proposed for aqueous sodium-ion batteries (ASIBs) towards low-temperature performance. Based on this dilute hybrid electrolyte and configured by bimetallic Prussian blue analogue (Ni2 ZnHCF) cathode and 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) anode, the full cell demonstrated surprising cycle performance with a specific capacity of 60 mAh g-1 (>800 cycles) and achieved prominent performance at low temperature. Glycerol effectively expanded the electrochemical stability window of the hybrid electrolyte to 2.7 V from formation of strong hydrogen bonds with water molecules and realized the operation of the cell at low temperature, delivering a stable reversible capacity of 40 mAh g-1 at -10 °C. The hybrid electrolyte of glycerol-water provides a new alternative in development of low-cost, long-lifespan, and low-temperature ASIBs and other aqueous battery systems.

Charge Carriers for Aqueous Dual-Ion Batteries.

Environmental and safety concerns of energy storage systems call for application of aqueous battery systems which have advantages of low cost, environmental benignity, safety, and easy assembling. Among the aqueous battery systems, aqueous dual-ion batteries (ADIBs) provide high possibility for achieving excellent battery performance. Compared with the "rocking chair" batteries with only one type of carrier involved in the charging and discharging, ADIBs with both cations and anions as charge carriers possess diverse selections of electrodes and electrolytes. Charge carriers are the basis of the configuration of ADIBs. In this Review, cations and anions that could be applied in ADIBs are demonstrated with corresponding electrode materials and favorable electrolytes. Some insertion mechanisms are emphasized to provide insights for the possibilities to enhance the practical performances of ADIBs.

In situ growing 3D-Cu coating to improve the reversibility and reaction kinetics of Zn metal anodes.

The zinc metal anode is the most promising metal anode material in aqueous battery systems due to its low cost and high theoretical capacity. However, it still undergoes irreversible reactions such as premature failure of the dendrites/dead Zn during Zn stripping/plating, resulting in the inferior cycling stability of the Zn-based full cell. Here, we demonstrate a facile 3D-Cu alloy coating to improve Zn reversibility by providing spatial voids to accommodate the plated Zn to form dendrite-free morphology. Combining the larger 3D surface and the alloying–dealloying process, the Zn anode reactions exhibit enhanced reaction kinetics to meet large operating current densities. The 3D-Cu-coated Zn anode can deliver improved cycling stability for 350 h under a large areal capacity of 3 mAh cm−2. It also enables MnO2–Zn at the full cell level to achieve a specific capacity of 205 mAh g−1 and longer cycling for 350 cycles with 87.4% retention of the initial capacity. This research provides a new pathway to achieve high reversible Zn metal chemistry.

Recent advances in Zn–CO2 batteries for the co-production of electricity and carbonaceous fuels

Electrochemical CO 2 reduction has been considered a promising approach to neutralizing the global CO 2 level. As an intriguing technique, metal-CO 2 battery devices can not only capture CO 2 into valuable carbonaceous chemicals and reduce the CO 2 concentration in the atmosphere but enable energy conversion. Among metal-CO 2 batteries, aqueous Zn–CO 2 batteries, especially rechargeable systems, exhibit flexible CO 2 electrochemistry in terms of multi-carbon chemicals, which are gaseous or water-soluble, in favor of rechargeability and cycling durability of aqueous battery systems. Despite the increasing number of publications on Zn–CO 2 batteries in the past three years, this field is still in its beginning stage and facing many challenges considering the capability of CO 2 fixation and battery performance. Herein, we present a timely and overall summary of the recent progress in Zn–CO 2 batteries, including fundamental mechanisms, affecting factors on electrochemical performance, catalyst cathodes, and electrolytes (catholytes and anolytes). Besides, we assess the application potential of Zn–CO 2 batteries and compare this with those of alkali metal-CO 2 batteries based on CO 2 fixation and battery performance. Finally, we point out some current challenges for the further development of Zn–CO 2 batteries and put forward perspectives of the research directions for practical applications of Zn–CO 2 batteries in the future.

A high-performance COF-based aqueous zinc-bromine battery

Aqueous zinc-bromine batteries can fulfil the energy storage requirement for sustainable techno-scientific advancement owing to its intrinsic safety and cost-effectiveness. Nevertheless, the uncontrollable zinc dendrite growth and spontaneous shuttle effect of bromine species have prohibited their practical implementation. Herein, we develop an aqueous zinc-bromine battery integrated with the exfoliated covalent organic framework (exCOF)-bromine cathode and COF-coated zinc metal anode. As verified by experimental and theoretical investigations, exCOF with abundant functional groups exhibits strong adsorption toward Br species, therefore immobilizes Br species and facilitates bidirectional conversion of polybromide. Meanwhile, the COF artificial layer on the surface of zinc metal anode can effectively regulate zinc flux and enable the uniform Zn deposition without dendrite growth. Consequently, owing to the synergistic effect of both COF-Zn anode and Br2-exCOF cathode, the as-assembled COF-Zn||Br2-exCOF full cell can deliver a remarkable capacity of ∼183 mAh g−1 (∼0.61 mAh cm−2) after 1000 cycles with capacity retention of ∼83 % at 2 A g−1 and high Coulombic efficiency of ∼99 %. Ultimately, this work can inspire insight into developing high-performance aqueous zinc-bromine battery systems.

Spectroscopic and Electrochemical Exploration of Carbon-Infused Intercalation-Type Spinel Composite for Aqueous Systems.

Lithium-manganese-based compounds are promising intercalation host materials for aqueous battery systems due to their synergy with high ionic conductive aqueous electrolytes, safety, eco-friendliness, and low cost. Yet, due to poor electrical conductivity and trapping of diffused electrolyte cations within its crystal formation, achieving optimum cycle stability and rate capability remains a challenge. This unfortunately limits their use in modern day high-powered devices, which require quality output with high reliability. Here, the authors propose a facile method to produce LiMn2O4 and LiFe0.5Mn0.5PO4 and compare their structural stability and corresponding electrochemical performance by controlling the interfacial layer through multi-walled carbon nanotubes’ (MWCNTs) infusion. High-resolution scanning electron microscopy results revealed that the active particles were connected by MWCNT via the formation of a three-dimensional wiring network, suggesting that stronger interfacial bonding exists within the composite. As a result, the conducting composite decreases the electron transport distance with an increased number of active sites, thus accelerating the lithium ion intercalation/de-intercalation process. Compared to C/LMO with a Rct of 226.3 Ω and change transfer (io) of 2.75 × 10−3, the C/LFMPO-composite has a reduced Rct of 138 Ω and enhanced rate of 1.86 × 10−4 A cm−2. The faster kinetics can be attributed to the unique synergy between the conductive MWCNTs and the contribution of both single-phase and two-phase regions in Li1-x(Fe,Mn)PO4 during Li+ extraction and insertion. The electrochemical features before and after modification correlate well with the interplanar distance of the expanded manganese and manganese phosphate layers shown by their unique surface features, as analyzed by advanced spectroscopy techniques. The results reveal that MWCNTs facilitate faster electron transmission whilst maintaining the stability of the host framework, which makes them favorable as next generation cathode materials.

In-situ crosslinked Zn2+-conducting polymer complex interphase with synergistic anion shielding and cation regulation for high-rate and dendrite-free zinc metal anodes

Aqueous Zn ion batteries hold great promise for next-generation energy storage systems. However, the uncontrolled Zn dendrite growth and adverse side reactions severely hinder their commercial application. Herein, a mixed organic electronic/ionic conductor interface consisting of Zn2+ crosslinked poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (ZPS) is in-situ formed on Zn metal surface, which can be used as a “cation–anion regulation” synergistic interface to protect Zn anodes. It is found that the ZPS interfacial layer has abundant negatively charged sulfonic groups and merit of cation permeability, which enables deanionization shock and effectively alleviates the side reactions. Density functional theory (DFT) calculations and finite elements method demonstrate that the ZPS interfacial layer prevents the local agglomeration of Zn2+ ions and makes the interfacial electric field evenly distributed, thereby enabling uniform Zn2+ flux and dendrite-free deposition. As a result, the modified Zn anode delivers an ultralong Zn plating/stripping cycling lifetime of 2200 h at 1 mA cm−2 and 1 mAh cm−2. Additionally, a long-term lifespan of 250 h is harvested even at an extremely high current of 20 mA cm−2. This work opens up a new field for the mixed organic electronic/ionic conductor in Zn anode protection and offers a promising strategy to accelerate the development of aqueous battery systems.

Research Development on Aqueous Ammonium‐Ion Batteries

AbstractAqueous rechargeable batteries (ARBs) are provided with the merits of low cost, inherent security, environmental friendliness, and excellent electrochemical properties. Among various aqueous battery systems, aqueous ammonium‐ion batteries (AIBs) have shown great potential in low‐cost energy storage systems for future large‐scale smart grid applications due to their unique advantages including resource affordability and quite competitive electrochemical performance and received extensive research attention during recent years. Their unique battery chemistry also brings new insights and understanding into exploration of electrode and battery design. However, research on aqueous AIBs is still in its infancy and there are still many scientific issues in AIBs system worth exploring. In this paper, the latest developments in electrode materials, electrolytes, and battery chemistry in AIBs are reviewed in detail timely. Then further challenges and opportunities are pointed out.

Grid-Scale Energy Storage Systems: Ensuring safety

Energy storage systems are becoming widely deployed throughout the electricity infrastructure. Large-scale integration of energy storage systems will become much more widespread as we begin to integrate larger amounts of renewables. Furthermore, electrification of the transportation sector will demand fast charging infrastructure and energy storage to handle new loads on distribution systems. However, energy storage systems, especially battery energy storage systems (BESSs), present a range of hazards that make engineering safety of large-scale systems a challenge. This article explores engineering safety of grid energy storage systems from the perspective of an asset owner and system operator. We review the hazards of common lithium-ion and aqueous battery system designs along with the state-of-the-art hazard mitigation methods. We also summarize the development of codes and standards to ensure safety and discuss best practices for emergency preparedness.

A rechargeable aqueous manganese-ion battery based on intercalation chemistry

Aqueous rechargeable metal batteries are intrinsically safe due to the utilization of low-cost and non-flammable water-based electrolyte solutions. However, the discharge voltages of these electrochemical energy storage systems are often limited, thus, resulting in unsatisfactory energy density. Therefore, it is of paramount importance to investigate alternative aqueous metal battery systems to improve the discharge voltage. Herein, we report reversible manganese-ion intercalation chemistry in an aqueous electrolyte solution, where inorganic and organic compounds act as positive electrode active materials for Mn2+ storage when coupled with a Mn/carbon composite negative electrode. In one case, the layered Mn0.18V2O5·nH2O inorganic cathode demonstrates fast and reversible Mn2+ insertion/extraction due to the large lattice spacing, thus, enabling adequate power performances and stable cycling behavior. In the other case, the tetrachloro-1,4-benzoquinone organic cathode molecules undergo enolization during charge/discharge processes, thus, contributing to achieving a stable cell discharge plateau at about 1.37 V. Interestingly, the low redox potential of the Mn/Mn2+ redox couple vs. standard hydrogen electrode (i.e., −1.19 V) enables the production of aqueous manganese metal cells with operational voltages higher than their zinc metal counterparts.