Cathode Materials For Zinc-ion Batteries Research Articles

Zn-doped hollow cubic MnO2 as a high-performance cathode material for Zn ion batteries.

Manganese-based compounds have the characteristics of high theoretical capacity, low cost and stable performance, thus become a research hotspot for cathode materials of zinc-ion batteries (ZIBs). However, in the process of charging and discharging, it is accompanied by problems such as structural collapse and low conductivity, which resulted in severe capacity degration during cycles. In this paper, a kind of Zn2+ doped MnO2 hollow cube cathode material (Zn-MnO2) was prepared by self-sacrificing template method. The Zn2+ doped in MnO2 crystals can induce oxygen vacancies in the structure, thereby improving the structural stability ion diffusion coefficient and electrical conductivity of the material. After 100 cycles at 0.3 A g-1, the high specific capacity of 281.2 mA h g-1 is still maintained. Through ex-situ XPS and ex-situ XRD tests, the mechanism of charge-discharge process was discussed. The results show that the storage mechanism of Zn-MnO2 is H+ and Zn2+ insertion/removal and Mn3+/Mn2+ two-electron reaction pathway. The total state density (TDOS) and partial state density (PDOS) of Zn-MnO2 and MnO2 further demonstrated that the doping of Zn2+ enhanced the electron conductivity and is beneficial to the electron transfer during the electrochemical reaction.

Sulfur-doped enhanced ZnMn2O4 spinel for high-capacity zinc-ion batteries: Facilitating charge transfer

ZnMn2O4 spinel is considered a promising cathode material for zinc-ion batteries due to its superior Zn2+ storage capability. However, the widespread utilization of ZnMn2O4 spinel as a high-capacity cathode material is impeded by its insufficient electrical conductivity. To tackle this limitation, we have employed a sulfur doping approach by substituting sulfur for oxygen atoms within the ZnMn2O4 lattice structure. After theoretical calculation, the charge exchange between metal Zn/Mn and surrounding coordinated atoms is enhanced after sulfur doping. The sulfur-doped ZnMn2O4 spinel effectively enhances the electrical conductivity, improving its electrochemical discharge capacity. Furthermore, the results reveals that a doping level of 20 % provided the greatest enhancement in capacitance, achieving a specific capacity of 220.1 mAh/g. This work improves the disadvantages of ZnMn2O4 at the atomic level and can provide ideas for the optimization and modification of spinel cathode materials.

ULPING-Based Titanium Oxide as a New Cathode Material for Zn-Ion Batteries

The need for alternative energy storage options beyond lithium-ion batteries is critical due to their high costs, resource scarcity, and environmental concerns. Zinc-ion batteries offer a promising solution, given zinc’s abundance, cost effectiveness, and safety, particularly its compatibility with non-flammable aqueous electrolytes. In this study, the potential of laser-ablation-based titanium oxide as a novel cathode material for zinc-ion batteries was investigated. The ultra-short laser pulses for in situ nanostructure generation (ULPING) technique was employed to generate nanostructured titanium oxide. This laser ablation process produced highly porous nanostructures, enhancing the electrochemical performance of the electrodes. Zinc and titanium oxide samples were evaluated using two-electrode and three-electrode setups, with cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge (GCD) techniques. Optimal cathode materials were identified in the Ti-5W (laser ablated twice) and Ti-10W (laser ablated ten times) samples, which demonstrated excellent charge capacity and energy density. The Ti-10W sample exhibited superior long-term performance due to its highly porous nanostructures, improving ion diffusion and electron transport. The potential of laser-ablated titanium oxide as a high-performance cathode material for zinc-ion batteries was highlighted, emphasizing the importance of further research to optimize laser parameters and enhance the stability and scalability of these electrodes.

Hierarchical nanostructure engineering endows ammonium vanadate as high capacity and ultra-long cycle cathode for wide-temperature aqueous zinc-ion batteries

Vanadium-based materials are the most promising cathode materials for Zinc-Ion batteries (ZIBs) due to their rich crystal structures and variable valence states. However, the structural collapse during multiple cycles leads to poor cycle life. Therefore, this work develops a 3-dimensional (3D) hierarchical nanostructure NH4V4O10 microspheres composed of nanosheets by a simple hydrothermal method, which are composed of nanosheets, this hierarchical nanostructure can promote the diffusion kinetics of Zn2+ and effectively mitigate the volume change of NH4V4O10 during the charging and discharging processes. As a result, the ZIBs assembled by the NH4V4O10 cathode exhibits high specific capacity of 522.9 mAh g−1 at 0.1 A g−1 and energy density of 348.96 Wh kg−1 at 215.12 W kg−1. At 20 A g−1, the NH4V4O10//Zn aqueous ZIB has 87.2 % capacity retention after 20,000 cycles. In addition, it exhibits excellent specific capacity and cycling performance over a wide-temperature range. At 10 A g−1, the NH4V4O10//Zn aqueous ZIB only loses 5.1 % capacity after 3500 cycles at −20 °C. Even at a high temperature of 50 °C, the capacity of NH4V4O10 battery is able to maintain 95.8 % after 450 cycles. This work informs the development of aqueous ZIBs for long cycle stability in a wide temperature range.

Sustainable Hydrothermal Synthesis of Reduced Graphene Oxide Wrapped on α‐MnO2 Nanorod Cathode for Zinc‐Ion Batteries

AbstractManganese oxide (α‐MnO2) with 1D tunneled cathode material is an attractive option for zinc ion batteries (ZIBs) as it offers high energy efficiency, cost‐effectiveness, natural abundance, safety, and environmental friendliness. However, it possesses inferior conductivity, which compromises its electrochemical performance in practical applications. To address this challenge, the integration of reduced graphene oxide is explored, renowned for its excellent conductivity, with α‐MnO2. This integration enhances the stability and conductivity of the composite structure. The reduction of graphene oxide is achieved through a hydrothermal method, facilitating the wrapping of reduced graphene oxide around α‐MnO2 nanorods. This synthesis approach not only saves energy but also aligns with the intended green approach. In this study, the impact of varying the hydrothermal reaction time on the properties of hydrothermally wrapped reduced graphene oxide on 1D α‐MnO2 (HWGOM) is investigated as a cathode material for ZIBs. A series of samples are prepared with hydrothermal reaction times of 4, 6, and 8 h, respectively. Specifically, HWGOM_6 demonstrates a highest specific capacity of 333 mAh g−1 at the current density of 200 mA g−1, along with remarkable cycling stability, retaining 94.3% of its capacity and achieving a coulombic efficiency of 97% over 500 cycles at a constant current density of 500 mA g−1.

Enhancing Zn2+/H+ Joint Charge Storage in MnO2: Concurrently Tailoring Mn's Local Electron Density and O's p-Band Center.

Enhancing proton storage in the zinc-ion battery cathode material of MnO2 holds promise in promoting its electrochemical performance by mitigating the intense Coulombic interaction between divalent zinc ions and the host structure. However, challenges persist in addressing the structural instability caused by Jahn-Teller effects and accurately modulating H+ intercalation in MnO2. Herein, the doping of high-electronegativity Sb with fully occupied d-orbital in MnO2 is reported. The Sb doping strategy engenders the formation of Mn-O-Sb path in the structure with a strong dipole polarization field, which facilitates the delocalization of eg orbital electron in Mn and thus mitigates the Jahn-Teller effects. Simultaneously, adjusting the level of Sb doping in MnO2 leads to modulation of the p-band center of O, optimizing its interaction with hydrogen and thereby enhancing proton storage. Consequently, MnO2 doped with 6% Sb exhibits commendable performance in both rate capability and cycling endurance, delivering 113 mAh g-1 at 2 A g-1 after 2000 cycles. This investigation underscores the crucial role of electronic structural engineering in elevating the electrochemical performance of cathode materials for zinc-ion batteries.

Tailored thickness engineering of Bi2Se3 nanosheets for superior cathodic performance in aqueous zinc-ion batteries

Bi2Se3 is considered a suitable cathode material for zinc-ion batteries (ZIBs) because of its high conductivity and large layer spacing. Herein, Bi2Se3 nanosheets with varying thicknesses are successfully synthesized using a one-step solvothermal process with adding different amounts of ethylenediamine. The introduction of ethylenediamine reduces the thickness of Bi2Se3 from 250 nm to 22.7 nm. The thin structure exposes more active sites and shortens ion transport paths. Therefore, the optimized Bi2Se3 nanosheet exhibits outstanding specific capacity (410 mA h g−1 at 0.2 A/g), high-rate performance (230 mA h g−1 at 5 A/g), and remarkable cycling stability (82.3 % capacity retention after 1200 cycles at 5 A/g). Furthermore, an in-depth exploration of cathodes during cycling is conducted to investigate the charge/discharge mechanism. A dynamic phase transition from Bi2Se3 to BiSe, accompanied by nanosheet exfoliation, is observed during the initial few cycles, designating BiSe as the primary active material. Moreover, an additional redox reaction involving multiple electrons has been proposed. This study offers a valuable guidance for utilizing Bi2Se3 as a cathode in ZIBs.

A Pyrophosphate Bifunctional Cathode with Inductive Effect for High-Voltage and Self-Charging Zinc Ion Battery.

With the growing demand for new energy storage devices, rechargeable aqueous zinc ion batteries (ZIBs) have attracted widespread attention due to their low cost and high safety. Among the cathode materials for ZIBs, polyanionic-based cathode materials with high voltage, high stability, and low cost have great potential. In this paper, tetragonal Na2VOP2O7 was prepared using a simple sol-gel method. The discharge platform voltage amounted to 1.8 V and had good rate and cycle performance due to the inductive effect of pyrophosphate. Then, a protective layer of Zn-hydroxyapatite (ZnHAP) modification was applied to the cathode surface, which can inhibit the hydrolysis of vanadium ions. The capacity was enhanced by 19 % after modification and the capacity retention after 100 cycles was also higher. Interestingly, the Na2VOP2O7 cathode also possesses a self-charging effect, recovering to 48 % of its initial capacity with an open-circuit voltage (OCV) of 1.1 V within a certain period, and light exposure can reduce the self-charging time by 83 %. These beneficial results indicate that the pyrophosphate bifunctional cathode with inductive effect has a great potential to construct high-voltage and multifunctional zinc ion battery.

MoS2/ReS2 Hollow Heterojunction for Enhanced Aqueous Zinc-Ion Storage Performance.

The research of cathode materials for water-based zinc ion batteries (ZIBs) is very hot because the current mainstream electrode makes it difficult to meet the requirements of high specific discharge capacity and maintain a stable structure in the electrochemical process. In this work, the cathode properties are adjusted by the modification idea of morphology regulation and heterojunction construction. The simple hydrothermal method is used to prepare the hollow bimetallic heterojunction nanospheres, and their electrochemical properties as cathode materials for ZIBs are studied for the first time. Herein, the optimized cathode delivers high-rate performance and long-term cycling stability (∼98.9% Coulombic efficiency at 0.1 A g-1 after 200 cycles). The results indicate that the hollow bimetallic heterojunction nanospheres can support the material structure and provide a wide Zn2+ migration channel. The excellent performance is because hollow heterojunction bimetallic sulfides can provide abundant catalytic active sites, improve the mobility of electrons, and enhance the battery performance fundamentally. Therefore, we firmly believe that the combination of the different modification ideas can coordinate to adjust the electrode performance of ZIBs, enriching the electrode types and expanding the energy system application range.

Designing MnO2@amorphous carbon core-shell structure as a cathode to enhance rate performance and cycling stability of aqueous zinc-ion batteries

Manganese dioxide has received significant attention as a prospective cathode material in aqueous zinc-ion batteries (ZIBs) owing to its elevated working voltage and commendable energy density. Nevertheless, challenges such as structural instability, manganese dissolution, and poor electrical conductivity remain significant barriers to the practical application of research. Here, the MnO2 nanorods encapsulated in the amorphous carbon (MnO2@C) with core-shell structure are prepared by a special hard template method, and investigated as cathode materials for ZIBs. The amorphous carbon, characterized by its structural defects and disorder, manifests heightened active site density, thereby establishing an efficient conduit for charge transport. Concurrently, the nano-dimensional interstitial spaces augment the active sites available for zinc insertion reactions, thereby effectively curtailing the ion diffusion path and, consequently, engendering heightened electrochemical performance. Moreover, the distinctive core-shell architecture of MnO2@C not only furnishes substantial spatial accommodation but also serves to alleviate volume alterations throughout charge and discharge events. Consequently, MnO2@C demonstrates outstanding electrochemical performance, with reversible capacities of 210 mAh·g−1 and 50 mAh·g−1 at 0.1 A·g−1 and 1.6 A·g−1, respectively. Furthermore, even after 600 cycles at 0.8 A·g−1, it maintains exceptional cycling performance, reaching 102 mAh·g−1, endowing MnO2@C cathodes with robust competitiveness in aqueous ZIBs.

Solvothermal Guided V2O5 Microspherical Nanoparticles Constructing High-Performance Aqueous Zinc-Ion Batteries.

Rechargeable aqueous zinc-ion batteries have attracted a lot of attention owing to their cost effectiveness and plentiful resources, but less research has been conducted on the aspect of high volumetric energy density, which is crucial to the space available for the batteries in practical applications. In this work, highly crystalline V2O5 microspheres were self-assembled from one-dimensional V2O5 nanorod structures by a template-free solvothermal method, which were used as cathode materials for zinc-ion batteries with high performance, enabling fast ion transport, outstanding cycle stability and excellent rate capability, as well as a significant increase in tap density. Specifically, the V2O5 microspheres achieve a reversible specific capacity of 414.7 mAh g-1 at 0.1 A g-1, and show a long-term cycling stability retaining 76.5% after 3000 cycles at 2 A g-1. This work provides an efficient route for the synthesis of three-dimensional materials with stable structures, excellent electrochemical performance and high tap density.

K-ion preintercalated MnO2 nanorods as a high-rate cathode material for aqueous zinc-ion batteries

The integration of Zn/α-MnO2 in aqueous zinc-ion batteries (ZIBs) has emerged as a promising avenue owing to their eco-friendliness, facile manufacturability, cost-effectiveness, low flammability, and commendable electrochemical performance. However, the intrinsic limitation in the rate capability of α-MnO2 constitutes a significant impediment to its practical application. In this study, we introduce K-ion preintercalated nanorods (K-MnO2-NR) with a diameter of approximately 10 nm as a cathode material for ZIBs. The synthesis of K-MnO2-NR entails a facile one-step electrochemical participation method, whereby K-ion are electrochemically intercalated into the tunnel-structured α-MnO2. The incorporation of K-ion serves a dual purpose of enhancing the electrical conductivity of manganese oxides and stabilizing the tunnel structure. Consequently, K-MnO2-NR manifests exceptional rate capability, exhibiting a specific capacity of 222 mAh g−1 at 2 A g−1, coupled with outstanding cycling stability (with negligible capacity decay observed over 1450 cycles at 2 A g−1). The facile and scalable synthesis process underscores its potential for large-scale production and eventual commercialization in pouch cells for energy storage applications.

Metal ions and organic molecule co-intercalated vanadium oxide cathode for high-performance zinc-ion batteries

Vanadium oxide is a highly promising cathode material for zinc-ion batteries due to its unique layered structure and high theoretical capacity. However, the material dissolution and structural collapse severely limit the development of zinc-ion batteries. Herein, inorganic metal ions (Mg2+) and organic polymer molecules (PANI) were introduced into the hydrated vanadium oxide interlayer in this paper. Mg2+ ions enhance the conductivity of the cathode and widen the interlayer spacing. Meanwhile, PANI serves to cushion the structural expansion resulting from ion embedding and stabilize the layered structure. Additionally, PANI actively participates in the charging and discharging process, thereby enhancing the diffusion rate of Zn2+. Thanks to the synergistic effect of Mg2+ and PANI, the MgVOH/PANI cathode exhibits a discharge capacity of 412 mAh·g−1 at 0.1 A g−1 and retains 93% of its capacity after 1000 cycles at a current density of 2A·g−1. This synergistic strategy of combining organic molecules and inorganic ions can provide a reference for improving the kinetic and structural stability of other aqueous battery cathodes.

2D Conductive Metal-Organic Frameworks Based on Tetraoxa[8]circulenes as Promising Cathode for Aqueous Zinc Ion Batteries.

Aqueous zinc-ion batteries (ZIBs) are the new generation electrochemical energy storage systems. Recently, two-dimensional conductive metal-organic frameworks (2D c-MOFs) are attractive to serve as cathode materials of ZIBs due to their compositional diversity, abundant active sites, and excellent conductivity. Despite the growing interest in 2D c-MOFs, their application prospects are still to be explored. Herein, a tetraoxa[8]circulene (TOC) derivative with unique electronic structure and interesting redox-active property are synthesized to construct c-MOFs. A series of novel 2D c-MOFs (Cu-TOC, Zn-TOC and Mn-TOC) with different conductivities and packing modes are obtained by combining the linker tetraoxa[8]circulenes-2,3,5,6,8,9,11,12-octaol (8OH-TOC) and corresponding metal ions. Three c-MOFs all exhibit typical semiconducting properties, and Cu-TOC exhibits the highest electrical conductivity of 0.2 S cm-1 among them. Furthermore, their electrochemical performance as cathode materials for ZIBs have been investigated. They all performed high reversible capacity, decent cycle stability and excellent rate capability. This work reveals the key insights into the electrochemical application potential of 2D c-MOFs and advances their development as cathode materials in ZIBs.

Recent development of manganese dioxide-based materials as zinc-ion battery cathode.

The development of advanced cathode materials for zinc-ion batteries (ZIBs) is a critical step in building large-scale green energy conversion and storage systems in the future. Manganese dioxide is one of the most well-studied cathode materials for zinc-ion batteries due to its wide range of crystal forms, cost-effectiveness, and well-established synthesis processes. This review describes the recent research progress of manganese dioxide-based ZIBs, and the reaction mechanism, electrochemical performance, and challenges of manganese dioxide-based ZIBs materials are systematically introduced. Optimization strategies for high-performance manganese dioxide-based materials for ZIBs with different crystal forms, nanostructures, morphologies, and compositions are discussed. Finally, the current challenges and future research directions of manganese dioxide-based cathodes in ZIBs are envisaged.

Ultra-low diffusion barrier tetramethyl ammonium cation-intercalated layered MnO2 for high-performance aqueous zinc-ion batteries

TMA+ pre-intercalated MnO2 displays enhanced diffusion kinetics, high capacity, and robust cycling stability as a cathode material for zinc-ion batteries.

The importance of electrolyte environment during in situ self-transformation for synthesizing V2O5·nH2O.

V2O5·nH2O is a promising cathode material for zinc-ion batteries. One of the synthesis methods of V2O5·nH2O is in situ self-transformation. In this communication, we focus on the influence of the electrolyte environment during in situ self-transformation (from VO2 to V2O5·nH2O). 2 M ZnSO4 and 2 M Zn(OTf)2 were used as different electrolytes to produce VOH-1 and VOH-2. VOH-1 expands in volume along the electric field to form a porous surface structure and shows low crystallinity along the (0 0 1) plane, while VOH-2 exhibits the opposite. These advantages enable the assembled batteries with VOH-1 to maintain excellent cycling performance at a rate of 2 A g-1 with a capacity of 500 mA h g-1 and stable cycling for 1800 cycles.

Room-temperature, one-step synthesis of Mn3O4 nanoparticles using morpholine as a complexing and precipitating agent: toward a cathode material for zinc-ion batteries

This study presents an eco-friendly synthesis of Mn3O4 nanoparticles via a 24-hour room-temperature reaction with morpholine and manganese nitrate. As a zinc-ion battery cathode, Zn//Mn3O4 showed a 209.7 mAh g−1 capacity after 300 cycles at 0.6 A g−1.

Cobalt-doped manganese(iii) oxide cathode materials with enhanced electrochemical performance for aqueous zinc-ion batteries

Co–Mn2O3 is prepared via a CoMn glycerate derivatization method as a cathode material for zinc-ion batteries, exhibiting enhanced diffusion kinetics, high capacity, and excellent cycling stability.

Enhancing the stability of zinc-ion batteries with titanium-doped VO2 cathode materials

Ti–VO2 is prepared by a hydrothermal method and used as a cathode material for zinc-ion batteries exhibiting enhanced diffusion kinetics, high capacity and excellent cycling stability.