Zinc Batteries Research Articles

NiCo2O4 on monolithic 3DGF/CNT for high performance hybrid zinc batteries

Hybrid Zn-Air and Zn-MX (MX refers to metal species with cation redox properties) batteries that combine the merits of both types are attracting increasing interest. However, the low areal capacity of the Zn-MX segment hinders their applications toward power resilience. Increasing the electrochemically active material loading is critical to achieving sufficient capacity but poses a challenge for conventional electrodes to maintain fast gas diffusion, which is necessary for the Zn-air function. Herein, we report an advanced, monolithic, carbon-based current collector by growing carbon nanotubes (CNT) onto a 3D graphene network (3DGF). The porous and highly conductive current collector readily accommodates more electrochemically active material, NiCo2O4 (NCO), thereby improving the Zn-NCO segment’s capacity without sacrificing the Zn-air segment’s performance. The 3DGF/CNT/NCO electrode was fabricated into a hybrid Zn battery which achieved a superior areal specific capacity of 2.87 mAh cm−2 at 5 mA cm−2, almost threefold of previously reported values, and an impressive rate capability and cycling stability with 98% of original capacity retained after 1000 cycles at 20 mA cm−2 charging/discharging current density. This work showcases 3DGF/CNT as an advanced current collector architecture for new and novel batteries.

A Functional Janus Ag Nanowires/Bacterial Cellulose Separator for High-Performance Dendrite-Free Zinc Anode Under Harsh Conditions.

Aqueous zinc-ion batteries (AZIBs) offer promising prospects for large-scale energy storage due to their inherent abundance and safety features. However, the growth of zinc dendrites remains a primary obstacle to the practical industrialization of AZIBs, especially under harsh conditions of high current densities and elevated temperatures. To address this issue, a Janus separator with an exceptionally ultrathin thickness of 29µm is developed. This Janus separator features the bacterial cellulose (BC) layer on one side and Ag nanowires/bacterial cellulose (AgNWs/BC) layer on the other side. High zincophilic property and excellent electric/thermal conductivity of AgNWs make them ideal for serving as an ion pump to accelerate Zn2+ transport in the electrolyte, resulting in greatly improved Zn2+ conductivity, deposition of homogeneous Zn nuclei, and dendrite-free Zn. Consequently, the Zn||Zn symmetrical cells with the Janus separator exhibit a stable cycle life of over 1000 h under 80mA cm-2 and are sustained for over 600 h at 10mA cm-2 under 50 °C. Further, the Janus separator enables excellent cycling stability in AZIBs, aqueous zinc-ion capacitors (AZICs), and scaled-up flexible soft-packaged batteries. This study demonstrates the potential of functional separators in promoting the application of aqueous zinc batteries, particularly under harsh conditions.

An electrolyte-rich nano-organic cathode constructs an ultra-high voltage Zinc-ion battery

To realize green and sustainable energy storage systems, it is urgent to propose emerging strategies to construct and understand the relationship between electrode materials and electrolytes. Based on the strategy of storing the electrolyte in an organic cathode, we prepare a Zn2+-doped polyaniline (PAZ) nano-organic cathode with a re-doping method, which possesses high crystallinity in the (010) plane and high conductivity compared with conventional H+-doped polyaniline (PA). The resultant Zn//PAZ battery exhibits outstanding electrochemical performance for 3000 cycles at an ultra-high voltage of 2.4 V, attributed to the enhancement of electrolyte concentration and reduction of free water stemming from the dedoping of PAZ. A hybrid charge storage mechanism including Zn2+ and multi-anions insertion/extraction is also demonstrated for the Zn//PAZ batteries during the charge/discharge process. To further expand the practical applications of the strategy, we manufacture an electrolyte-free Zn//PAZ battery, which achieves acceptable performance for 400 cycles. This research provides insight into the relationship between the electrolyte and re-doped polyaniline organic cathode and opens a new avenue for emerging Zinc batteries.

Influencing ionic conductivity and mechanical properties of ionic liquid polymer electrolytes by designing the chemical monomer structure

ABSTRACTPolymeric single chloride-ion conductor networks based on acrylic imidazolium chloride ionic liquid monomers AACXImCYCl as reported previously are prepared. The chemical structure of the polymers is varied with respect to the acrylic substituents (alkyl spacer and alkyl substituent in the imidazolium ring). The networks are examined in detail with respect to the influence of the chemical structure on the resulting properties including thermal behavior, rheological behavior, swelling behavior, and ionic conductivity. The ionic conductivities increase (by two orders of magnitude from 10−6 to 10−4 S·cm−1 with increasing temperature), while the complex viscosities of the polymer networks decrease simultaneously. After swelling in water for 1 week the ionic conductivity reaches values of 10−2 S·cm−1. A clear influence of the spacer and the crosslinker content on the glass transition temperature was shown for the first time in these investigations. With increasing crosslinker content, the Tg values and the viscosities of the networks increase. With increasing spacer length, the Tg values decrease, but the viscosities increase with increasing temperature. The results reveal that the materials represent promising electrolytes for batteries, as proven by successful charging/discharging of a p(TEMPO-MA)/zinc battery over 350 cycles.

A Reversible Six-Electron Transfer Cathode for Advanced Aqueous Zinc Batteries.

The electrochemical reactions for the storage of Zn2+ while embracing more electron transfer is a foundation of the future high-energy aqueous zinc batteries (AZBs). Herein, we report a six-electron transfer electrochemistry of nano-sized TeO2/C (n-TeO2/C) cathode by facilitating the reversible conversion of TeO2↔Te and Te↔ZnTe. Benefitting from the integrated conductive nanostructure and the proton-rich environment in providing optimized electrochemical kinetics (facilitated Zn2+ uptake and high electronic conductivity) and feasible thermodynamic process (low Gibbs free energy), the as-prepared n-TeO2/C with stable cycling performance exhibits a superior reversible capacity of over 800mAh g-1 at 0.1 A g-1. A precise understanding of the reaction mechanism via ex-situ and in-situ characterizations presents that the reversible six-electron transfer reaction is proton-dependent, and a proton generating and consuming mechanism of three-phase conversion n-TeO2/C in the acidic electrolyte is thoroughly revealed.

A Minireview of the Solid-State Electrolytes for Zinc Batteries.

Aqueous zinc-ion batteries (ZIBs) have gained significant recognition as highly promising rechargeable batteries for the future due to their exceptional safety, low operating costs, and environmental advantages. Nevertheless, the widespread utilization of ZIBs for energy storage has been hindered by inherent challenges associated with aqueous electrolytes, including water decomposition reactions, evaporation, and liquid leakage. Fortunately, recent advances in solid-state electrolyte research have demonstrated great potential in resolving these challenges. Moreover, the flexibility and new chemistry of solid-state electrolytes offer further opportunities for their applications in wearable electronic devices and multifunctional settings. Nonetheless, despite the growing popularity of solid-state electrolyte-based-ZIBs in recent years, the development of solid-state electrolytes is still in its early stages. Bridging the substantial gap that exists is crucial before solid-state ZIBs become a practical reality. This review presents the advancements in various types of solid-state electrolytes for ZIBs, including film separators, inorganic additives, and organic polymers. Furthermore, it discusses the performance and impact of solid-state electrolytes. Finally, it outlines future directions for the development of solid-state ZIBs.

A Reversible Six‐Electron Transfer Cathode for Advanced Aqueous Zinc Batteries

AbstractThe electrochemical reactions for the storage of Zn2+ while embracing more electron transfer is a foundation of the future high‐energy aqueous zinc batteries. Herein, we report a six‐electron transfer electrochemistry of nano‐sized TeO2/C (n‐TeO2/C) cathode by facilitating the reversible conversion of TeO2↔Te and Te↔ZnTe. Benefitting from the integrated conductive nanostructure and the proton‐rich environment in providing optimized electrochemical kinetics (facilitated Zn2+ uptake and high electronic conductivity) and feasible thermodynamic process (low Gibbs free energy change), the as‐prepared n‐TeO2/C with stable cycling performance exhibits a superior reversible capacity of over 800 mAh g−1 at 0.1 A g−1. A precise understanding of the reaction mechanism via ex situ and in situ characterizations presents that the reversible six‐electron transfer reaction is proton‐dependent, and a proton generating and consuming mechanism of three‐phase conversion n‐TeO2/C in the weakly acidic electrolyte is thoroughly revealed.

Unlocking Anionic Redox by Breaking Metal–Oxygen Bonds in Aqueous Zinc Batteries

Unlocking Anionic Redox by Breaking Metal–Oxygen Bonds in Aqueous Zinc Batteries

Fluoride-Rich, Organic-Inorganic Gradient Interphase Enabled by Sacrificial Solvation Shells for Reversible Zinc Metal Batteries.

Zinc metal batteries are strongly hindered by water corrosion, as solvated zinc ions would bring the active water molecules to the electrode/electrolyte interface constantly. Herein, we report a sacrificial solvation shell to repel active water molecules from the electrode/electrolyte interface and assist in forming a fluoride-rich, organic-inorganic gradient solid electrolyte interface (SEI) layer. The simultaneous sacrificial process of methanol and Zn(CF3SO3)2 results in the gradient SEI layer with an organic-rich surface (CH2OC- and C5 product) and an inorganic-rich (ZnF2) bottom, which combines the merits of fast ion diffusion and high flexibility. As a result, the methanol additive enables corrosion-free zinc stripping/plating on copper foils for 300 cycles with an average coulombic efficiency of 99.5%, a record high cumulative plating capacity of 10 A h/cm2 at 40 mA/cm2 in Zn/Zn symmetrical batteries. More importantly, at an ultralow N/P ratio of 2, the practical VO2//20 μm thick Zn plate full batteries with a high areal capacity of 4.7 mAh/cm2 stably operate for over 250 cycles, establishing their promising application for grid-scale energy storage devices. Furthermore, directly utilizing the 20 μm thick Zn for the commercial-level areal capacity (4.7 mAh/cm2) full zinc battery in our work would simplify the manufacturing process and boost the development of the commercial zinc battery for stationary storage.

Understanding the Role of Zinc Hydroxide Sulfate and its Analogues in Mildly Acidic Aqueous Zinc Batteries: A Review.

Mildly acidic aqueous zinc batteries (AZBs) have attracted tremendous attention for grid storage applications with the expectation to tackle the issues of Li-ion batteries on high cost and poor safety. However, the performance, particularly energy density and cycle stability of AZBs are still unsatisfactory when compared with LIBs. To help the development of AZBs, a lot of effort have been made to understand the battery reaction mechanisms and precedent microscopic and spectroscopic analyses have shown flake-like large particles of zinc hydroxide sulfate (ZHS) and its analogues formed on the surfaces of cathodes and anodes in sulfate and other electrolyte systems during cycling. However, because of the complexity of the thermodynamics and kinetics of aqueous reactions to understand different battery conditions, controversies still exist. This article will review the roles of ZHS discussed in recent representative references aiming to shine light on the fundamental mechanisms of AZBs and pave ways to further improve the battery performance.

Multi redox and oxygen vacancies govern the highly active manganese doped SrTiO3 cathode in rechargeable alkaline zinc battery

Rechargeable alkaline zinc batteries (RAZBs) have been facing big challenges of low energy density even they are inexpensive and safe. SrTiO3 has aroused strong interests as cathode of RAZBs based on their promising properties of strong redox properties and better thermal stability. However, the low electric conductivity and inadequate access sites of SrTiO3 limit their applications. Herein, Mn is successfully doped into SrTiO3 using facile one-pot hydrothermal method, which functions as an advanced cathode for RAZBs. In comparison with SrTiO3, partial substitution of Mn for Ti site in SrTiO3 lattice can endow SrTiO3 with enhanced electric conductivity, improved specific surface area as well as active sites of the SrTiO3. This is due to discovery of multi redox reaction of Mn and lattice vacancies. As a result, the Zn//Mn-STO battery demonstrate an excellent capacity of 744 mA h cm−3, good stability, and high energy density of 90 mWh cm−3. These outperforming of Mn-STO as cathode holding a great potential to prepare high-performance battery for future portable electronics.

Highly effective Cu doped SrTiO3 as a cathode driven by oxygen vacancies and redox of Ti4+/Ti3+ and Cu2+/Cu+ for rechargeable alkaline zinc batteries

There is great demand for environmental concerns and explosion hazard batteries. Rechargeable alkaline zinc batteries (RAZBs) have gained significant attention due to their exceptional characteristics such as affordability, safety features, and high theoretical gravimetric capacity. However, practically RAZBs still exhibit poor capacities and limited rechargeability. In this study, copper-doped SrTiO3 (Cu-STO) was successfully synthesized via facile hydrothermal method to be used as a cathode in RAZBs. The capacity of RZABs has enhanced up to 208 mAh g−1 (0.2 A g−1) or 1.5 folds as compared to that of pristine SrTiO3. This is attributed to the presence of oxygen vacancies (Vö) which facilitate the activation of redox-active sites involving Ti4+/Ti3+ and Cu2+/Cu+ ions. Moreover, the fast ions diffusion and good conductivity enable high capacity and rechargeability. Thus, RAZBs showed good rechargeability even after 1000 cycles under 1 A g−1. This provides the underlying potential of Cu-STO as cathode in RAZBs.

Quinoxaline derivatives as cathode for aqueous zinc battery

Quinoxaline derivatives as cathode for aqueous zinc battery

Electrochemical Performance and Mechanism of Bimetallic Organic Framework for Advanced Aqueous Zn Ion Batteries.

Widespread interest has been generated by aqueous zinc batteries (AZIBs), which have excellent theoretical capacities (820 mA h g-1), a low redox potential (-0.76 V vs SHE of Zn metal), and high security. Suitable cathodes for constructing high performance AZIBs are of great signification. Metal-organic frameworks (MOFs) with adjustable structure via metals and organic units show great potential in AZIBs. In this work, ZnMn-Squaric acid (ZnMn-SQ) was synthesized using squaric acid through coprecipitation and served as the cathode for AZIBs. The ZnMn-SQ electrode demonstrated a high capacity of 489.1 mA h g-1 at 0.2 A g-1. Meanwhile, ZnMn-SQ can obtain 80.7 mA h g-1 after 1300 cycles, showing an outstanding long cycle life. More importantly, ex situ characterizations of XRD, XPS, and FT-IR revealed that ZnMn-SQ undergoes a structural transformation from the initial ZnMn-SQ framework to manganese oxide accompanied by Zn-SQ and then reduced to MnOOH, ZnMn2O4, and Zn4SO4(OH)6·5H2O (ZHS) in subsequent cycles. In addition, a modified zinc anode using cubic porous Zn-SQ-3d was used to construct ZnMn-SQ // Zn-SQ-3d@Zn(Zn-SQ-3d-coated Zn) high performance AZIBs, the capacity of which reaches 171.3 mA h g-1 at 1 A g-1 after 660 cycles. This work provided chances for constructing high-performance zinc ion batteries using MOF compounds.

Polyhydroxylated Organic Molecular Additives for Durable Aqueous Zinc Battery

AbstractThe large‐scale deployment of aqueous Zn‐ion batteries is hindered by Zn anode instability including surface corrosion, hydrogen gas evolution, and irregular Zn deposition. To tackle these challenges, a polyhydroxylated organic molecular additive, trehalose, is incorporated to refine the solvation structure and promote planar Zn deposition. Within solvation structure regions involving trehalose, the hydroxy groups participate in the reconstruction of hydrogen bond networks, which increases the overpotential for water decomposition reaction. Moreover, at the Zn metal–molecule interface, the chemisorption of trehalose onto the surface of the zinc anode enhances corrosion resistance and facilitates the deposition of zinc in a planar manner. The optimized electrolyte significantly improves Zn striping/plating reversibility and maintains stable potentials over 1600 h at 5 mA cm−2 with a cutoff capacity of 1 mA h cm−2 in symmetric cells. When combined with the MnO2 cathode, the assembled coin cell retains ≈89% of its capacity after 1000 cycles. This organic molecule additive, emphasizing the role of polyhydroxylated organic molecules in fine‐tuning solvation structures and anode/electrolyte interfaces, holds promise for enhancing various aqueous metal batteries.

Multifunctional 3D electrodes for tunable high-performance hybrid zinc batteries

The high energy density and long cycling life of zinc-based batteries are restricted by the single electrochemical reaction system. To improve the electrochemical performance of batteries, electrode materials, electrolytes and membranes are regularly modified, while the construction of battery systems is often neglected. Herein, a multifunctional electrode was prepared via 3D printing, which successfully coupled the metal oxide/hydroxide-zinc battery (MZB) reaction and rechargeable zinc-air battery (RZAB) reaction. The ultrathick hierarchical 3D electrode provided a tunable capacity for the MZB system, which enabled the possibility for feasible output regulation of this hybrid system. The active material NiCoLDH was discovered to undergo structure reconstruction during cycling, which revealed the capacity fading mechanism. The delicate system design and discovery ensured a high-performance battery configuration and revealed the corresponding mechanism, opening a new avenue for developing high-performance zinc batteries.

Partial Sulfidation of the Electrochemically Exfoliated Layered Double Hydroxides toward Advanced Aqueous Zinc Batteries

AbstractAqueous zinc‐based batteries are a promising alternative to lithium batteries. These batteries, however, persistently suffer from uncontrollable dendrite growth and sustained water consumption at the Zn anodes, along with low and often fading capacity at the cathodes. Herein, Zn metal is simply encapsulated into a chitosan‐containing polymer gel that not only suppresses hydrogen evolution but also enables dendrite‐free Zn plating/stripping. A binder‐free cathode based on the electrochemically exfoliated and partially sulfidated Ni–Co–Fe layered double hydroxide‐reduced graphene oxide (SNS‐rGO) nanocomposite is also reported. The fabricated devices (based on either Zn or chitosan‐coated Zn) deliver near record‐high values of specific capacity (756 mA h g−1cathode at 1 A g−1) and specific energy (1284 W h kg−1cathode), along with an outstanding specific power (108 kW kg−1cathode), an excellent output voltage (up to 1.9 V), and prolonged cycling stability at 100% depth‐of‐discharge. This interface engineering strategy, supported by the density functional theory calculations, provides a solid basis for further practical applications of aqueous Zn batteries.

3D Printing of MXene‐Enhanced Ferroelectric Polymer for Ultrastable Zinc Anodes

AbstractZinc (Zn) metal anodes of aqueous zinc‐ion batteries (AZIBs) have attracted significant attention due to their high theoretical capacities, low redox potentials, and low cost. However, uncontrollable dendrite formation and side reactions can result in limited reversible cycling and quick failure of the batteries. Herein, a polyvinylidene fluoride (PVDF)‐based protection layer (PVDF‐MXene) with high β‐phase content is built by the 3D printing method. The synergistic effect attributed to the 3D printing approach and MXene nanosheets contributes to phase transition of the PVDF polymer chains from α‐phase to β‐phase, improving the ferroelectric properties of the printed PVDF films. Such a protection layer can manipulate the concentration distribution of zinc ions and enable the uniform growth of zinc plates. As a result, symmetrical zinc batteries using such anodes (PVDF‐MXene‐Zn) exhibit reversible Zn plating/stripping with low voltage hysteresis at 1.0 mA cm−2, 1.0 mAh cm−2 for over 4200 h, and a high‐rate capability up to 10 mA cm−2. When assembled with MnO2 and activated carbon, the resulting Zn‐MnO2 battery and zinc‐ion capacitor exhibited significantly enhanced cycling stability. The proposed strategy in this study provides a novel strategy for the protection of the zinc anode, thus promoting the practical application of ZIBs.

Mechanism of Chalcophanite Nucleation in Zinc Hydroxide Sulfate Cathodes in Aqueous Zinc Batteries.

Aqueous Zn-ion batteries with MnO2-based cathodes have seen significant attention owing to their high theoretical capacities, safety, and low cost; however, much debate remains regarding the reaction mechanism that dominates energy storage. In this work, we report our electron microscopy study of cathodes containing zinc hydroxide sulfate (Zn4SO4(OH)6·xH2O, ZHS) together with carbon nanotubes cycled in electrolytes containing ZnSO4 with varied amounts of MnSO4 incorporated. The primary Mn-containing phase is formed in situ in the cathode during cycling, where a dissolution-deposition reaction is identified between ZHS and chalcophanite (ZnMn3O7·3H2O). Mechanistic details of this reaction, in which the chalcophanite nucleates then separates from the ZHS flakes as the ZHS dissolves while acting as the primary Zn source for the reaction, are revealed using surface sensitive methods. These findings indicate the reaction is local to the ZHS flakes, providing new insight toward the importance of ZHS and the cathode microstructure.

Self‐Smoothing Deposition Behavior Enabled by Beneficial Potential Compensating for Highly Reversible Zn‐Metal Anodes

AbstractRealizing compact dendrite‐free zinc (Zn) plating is crucial to avoiding premature battery failure caused by internal short‐circuits, which is highly determined by the interface electric field (ψi) distribution. Herein, a concept of “potential compensating” is shown on Zn anodes to stimulate its self‐smoothing deposition behavior for durable batteries. A homogeneous ψi with elevated potential intensity is successfully built at the Zn/electrolyte interface via the selective adsorption of highly polarized propylene glycol (PG) molecules, which facilitate the formation of dense and uniform Zn electroplating patterns. Moreover, the PG additive can simultaneously reshape the structure of Zn2+‐solvation sheath and immobilize the H‐bonding networks in bulk electrolyte, enabling Zn anodes with exceptional electrochemical reversibility (99.6%) and ultralong calendar life (3500 h), as revealed by joint spectroscopic and electrochemical analyses. More importantly, full cells with PG safeguard can deliver desirable cycling stability even at an elevated temperature (50 °C) and low N/P ratios (cathode mass loading up to 14.38 mg cm−2). This study presents new insight into the rational design of stable practical electrolytes and interfacial chemistry regulation for sustainable zinc batteries.