Rechargeable Zn-ion Batteries Research Articles

Vanadium hexacyanoferrate with two redox active sites as cathode material for aqueous Zn-ion batteries

Aqueous rechargeable Zn-ion batteries (ARZIBs) are attractive due to their low cost, high safety and environmental friendliness. However, the development of ARZIBs still faces many challenges. One of the biggest challenges is to find suitable cathode materials for reversible Zn2+ ions insertion/extraction. In this work, we synthesize a Prussian blue analogue (PBA) with a new chemical composition, vanadium hexacyanoferrate (VHCF), via a simple co-precipitation method and study its performance as a cathode material for an aqueous rechargeable Zn-ion battery. The VHCF with two electrochemical redox active sites, V and Fe, delivers a three-electron redox reaction with a capacity of 187 mA h g−1 at current density of 0.5 A g−1. Even at a current rate of 5 A g−1, VHCF can still deliver a large capacity of 122 mA h g−1. The Zn//VHCF battery also exhibits a long cycle life of 1000 cycles with excellent capacity retention of 87.8% and a high Coulombic efficiency close to 100%. During the first charging process, the cubic structure of VHCF changes to a rhombohedral phase, a structure where the Zn2+ ions can be reversibly inserted into and extracted from in subsequent cycles. The promising performances make VHCF an attractive candidate as cathode material for ARZIBs system.

(Invited) Rechargeable Zn-Ion Batteries Via Multifunctional 3D Electrodes and Mixed-Salt Electrolytes

We recently demonstrated that advanced multifunctional 3D MnOx@carbon nanofoam (MnOx@CNF) electrodes cycled in mixed-salt aqueous electrolytes [1] extend the performance advantages of rechargeable “zinc-ion” batteries, an emerging energy-storage technology with inherent cost and safety benefits. [2],[3] The combination of the multifunctional birnessite-MnOx@CNF and mild-pH Zn2+-containing electrolyte results in a complex charge-storage mechanism in which a H+ inserts into the birnessite-MnOx during discharge, resulting in an increase in the local pH that triggers precipitation of Zn4(OH)6SO4·5H2O, while Na-ions support pseudocapacitance reactions. [4] This dual charge-storage mechanism yields high capacity at low rates (308 mA h g-1 at 1C, MnOx theoretical capacity) and pulse power at high rates (100 mA h g-1 at 20C) via pseudocapacitance; these mechanisms are reversible over hundreds of cycles, attributed in part to the through-connected pore structure of the CNF. In order to explore the efficacy of other MnOx polymorphs in such 3D multifunctional electrode designs, we developed an “in-place” conversion to generate nanocrystalline ZnMn2O4 spinel from the birnessite-MnOx coating on the CNF. Crystallization is achieved by heating at relatively mild temperatures (300°C), such that the nanoscale morphology of the original MnOx coating and through-connected pore structure of the underlying CNF are maintained. We used a suite of ex-situ characterization methods (SEM/EDS, XRD, XPS) to elucidate the charge-storage reaction of ZnMn2O4@CNF in 1 M ZnSO4 and found that it is even more complex than the charge-storage mechanism of birnessite-MnOx@CNF. Discharge of ZnMn2O4@CNF proceeds via two steps, the first occurring by Zn2+ insertion into the spinel and the second by H+ insertion accompanied by Zn4(OH)6SO4·5H2O precipitation; the reaction reverses upon recharge. We will discuss the implications of these mechanisms for such performance characteristics as rate capability and cycle life in their ultimate application as positive electrodes in next-generation zinc-ion batteries. [1]. J.S. Ko, M.B. Sassin, J.F. Parker, D.R. Rolison, and J.W. Long: Combining battery-like and pseudocapacitive charge storage in 3D MnOx@carbon electrode architectures for zinc-ion cells. Sustainable Energy Fuels 2, 626–636 (2018). [2]. B. Tang, L. Shan, S. Liang, and J. Zhou: Issues and opportunities facing aqueous zinc-ion batteries. Energy Environ. Sci. 12, 3288–3304 (2019). [3]. L. E. Blanc, D. Kundu, and L. F. Nazar: Scientific Challenges for the Implementation of Zn-Ion Batteries. Joule 4 , 771–799 (2020). [4]. J.S. Ko, M.D. Donakowski, M.B. Sassin, J.F. Parker, D.R. Rolison, and J.W. Long: Deciphering charge-storage mechanisms in 3D MnOx@carbon electrode nanoarchitectures for rechargeable zinc-ion cells. MRS Communications 9, 99–106 (2019).

Potentiodynamics of the Zinc and Proton Storage in Disordered Sodium Vanadate for Aqueous Zn-Ion Batteries.

A rechargeable Zn-ion battery is a promising aqueous system, where coinsertion of Zn2+ and H+ could address the obstacles of the sluggish ionic transport in cathode materials imposed by multivalent battery chemistry. However, there is a lack of fundamental understanding of this dual-ion transport, especially the potentiodynamics of the storage process. Here, a quantitative analysis of Zn2+ and H+ transport in a disordered sodium vanadate (NaV3O8) cathode material has been reported. Collectively, synchrotron X-ray analysis shows that both Zn2+ and H+ storages follow an intercalation storage mechanism in NaV3O8 and proceed in a sequential manner, where intercalations of 0.26 Zn2+ followed by 0.24 H+ per vanadium atom occur during discharging, while reverse dynamics happens during charging. Such a unique and synergistic dual-ion sequential storage favors a high capacity (265 mA h g-1) and an energy density (221 W h kg-1) based on the NaV3O8 cathode and a great cycling life (a capacity retention of 78% after 2000 cycles) in Zn/NaV3O8 full cells.

Ammonium ion intercalated hydrated vanadium pentoxide for advanced aqueous rechargeable Zn-ion batteries

Considering many factors, including environmental protection, high cost, and limited resource, aqueous rechargeable Zn-ion batteries (ARZIBs) are expected to be a new next-generation grid to replace Li-ion batteries. The open layered framework of (metal ions intercalated) hydrated vanadium pentoxides is conducive to the transfer and diffusion of zinc ions, making this kind of material a promising cathode material. In this work, ammonium ion (NH4+) intercalated hydrated vanadium pentoxide [(NH4)xV2O5·nH2O, abbreviated as NVOH] is prepared by a comparatively low-temperature synthesis and developed as a cathode material for ARZIBs. The influence of different types and concentrations of zinc salt electrolytes on the electrochemical performance is first studied, demonstrating that 3 M Zn(CF3SO3)2 shows the most excellent performance. The Zn//NVOH battery delivers superior electrochemical reversibility, a high specific capacity (372 mAh·g-1 at 0.1 A·g-1), a preeminent energy density (273 Wh·kg-1 at 155 W·kg-1), and a long lifespan cycling performance (175 mAh·g-1 after 2,000 cycles at 5 A·g-1), which is superior to or comparable to most up-to-the-minute V-based materials applied to ARZIBs. The intercalation reversibility of zinc ion is proved during the electrochemical reaction by various characteristic measurements. This work not only provides a low-temperature hydrothermal synthesis route (100 °C) for NVOH but also demonstrates that it can be a promising supplement for zinc ion batteries or other portable battery devices.

Layered TiS2 as a Promising Host Material for Aqueous Rechargeable Zn Ion Battery

The aqueous zinc-ion battery (ZIB) is one of several promising energy storage systems because of its low cost, nontoxicity, and high safety. In addition, Zn metal exhibits low redox potential in aqueous solution. However, one big obstacle in the development of ZIBs is the dendrite growth and corrosion reaction of Zn anode. Exploration of the Zn host anode material with high reversible capacity and low redox voltage would be an effective strategy. Herein, layered TiS2 is successfully demonstrated as a durable host material for neutral aqueous ZIBs with a relatively low charge voltage of 0.4 V. The TiS2 material delivers a stabilized capacity of 120 mAh g–1 at 100 mA g–1, high rate capability (76 mAh g–1 at 1000 mA g–1), and good cycle performance (70% capacity retention after 500 cycles at 1000 mA g–1) in a Zn/TiS2 cell. The outstanding electrochemical properties are attributed to the excellent maintenance of TiS2 during cycling in which the Zn2+ cations can be easily inserted/extracted into/from the layered structure with slight structural change, observed from ex situ X-ray diffraction investigation. Mechanism study reveals that TiS2 goes through a reversible (de)­interclation reaction in accompany with valence change of titanium element during cycling. This study would benefit the exploration and design of host materials for rechargeable aqueous batteries, especially for the anode.

Highly stable aqueous rechargeable Zn-ion battery: The synergistic effect between NaV6O15 and V2O5 in skin-core heterostructured nanowires cathode

Abstract The aqueous rechargeable Zn-ion batteries based on the safe, low cost and environmental benignity aqueous electrolytes are one of the most compelling candidates for large scale energy storage applications. However, pursuing suitable insertion materials may be a great challenge due to the strong electrostatic interaction between Zn2+ and cathode materials. Hence, a novel NaV6O15/V2O5 skin-core heterostructure nanowire is reported via a one-step hydrothermal method and subsequent calcination for high-stable aqueous Zn-ion batteries (ZIBs). The NaV6O15/V2O5 cathode delivers high specific capacity of 390 mAh/g at 0.3 A/g and outstanding cycling stability of 267 mAh/g at 5 A/g with high capacity retention over 92.3% after 3000 cycles. The superior electrochemical performances are attributed to the synergistic effect of skin-core heterostructured NaV6O15/V2O5, in which the sheath of NaV6O15 possesses high stability and conductivity, and the V2O5 endows high specific capacity. Besides, the heterojunction structure not only accelerates intercalation kinetics of Zn2+ transport but also further consolidates the stability of the layers of V2O5 during the cyclic process. This work provides a new perspective in developing feasible insertion materials for rechargeable aqueous ZIBs.

Achieving high capacity and long life of aqueous rechargeable zinc battery by using nanoporous-carbon-supported poly(1,5-naphthalenediamine) nanorods as cathode

Aqueous rechargeable Zn-ion batteries (ZIBs) are safe, low cost, and environmentally friendly, yet the realization of both high capacity and long cycling life remains a major challenge. Herein, electrodeposited poly(1,5-naphthalenediamine) nanorods over nanoporous carbon are used as the cathode material to make aqueous ZIBs that can be operated within the voltage range of 0.1 – 1.8 ​V and have merits of both ionic battery and supercapacitor. Flexible carbon fiber fabric and thick carbon fiber felt are used as current collectors, respectively, to support the polymer/carbon composite with different mass loadings. With using the carbon fabric, flat pouch cells and cable-shaped micro cells are fabricated and show stable electrochemical performances when repeatedly bent at large angles. The pouch cells show maximum energy and power densities of 195 ​Wh kg‒1 and 104 ​W ​kg–1, respectively, and achieve a capacity retention of 91% after 10000 cycles. The prototype cell with using a 3 ​mm-thick carbon felt shows higher energy densities up to 7.7 ​mWh cm‒2 and better cycling stability, i.e., 100% capacity retention after 10000 cycles. Also, insights into the charge storage mechanism and superb cycling stability of our new polymer cathode are given.

Self-Recovery Chemistry and Cobalt-Catalyzed Electrochemical Deposition of Cathode for Boosting Performance of Aqueous Zinc-Ion Batteries.

SummaryRechargeable Zn-ion batteries working with manganese oxide cathodes and mild aqueous electrolytes suffer from notorious cathode dissolution during galvanostatic cycling. Herein, for the first time we demonstrate the dynamic self-recovery chemistry of manganese compound during charge/discharge processes, which strongly determines the battery performance. A cobalt-modified δ-MnO2 with a redox-active surface shows superior self-recovery capability as a cathode. The cobalt-containing species in the cathode enable efficient self-recovery by continuously catalyzing the electrochemical deposition of active Mn compound, which is confirmed by characterizations of both practical coin-type batteries and a new-design electrolyzer system. Under optimized condition, a high specific capacity over 500 mAh g−1 is achieved, together with a decent cycling performance with a retention rate of 63% over 5,000 cycles. With this cobalt-facilitated deposition effect, the battery with low concentration (0.02 M) of additive Mn2+ in the electrolyte (only 12 atom % to the overall Mn) maintains decent capacity retention.

Facile hydrothermal synthesis and electrochemical properties of (NH4)2V6O16 nanobelts for aqueous rechargeable zinc ion batteries

Aqueous rechargeable Zn-ion batteries (ARZIBs) have attracted great attention owing to many advantages including environmental protection, low cost and safety. Ammonium vanadates with multi-oxidation valence and open-framework layered structure, which is beneficial for zinc storage performance, are chosen as alternative candidates of cathode materials. (NH4)2V6O16 has received some attention in Li-ion battery, however, the electrochemical properties of (NH4)2V6O16 applied to ARZIBs has rarely reported comparatively. In this work, (NH4)2V6O16 nanobelts are prepared through a facile hydrothermal method and reported as the cathode material in ARZIBs. The Zn/(NH4)2V6O16 battery displays a wonderful rate capability with a staged reversible capacity of 322.0, 300.8, 267.5, 239.3, 209.2 mA h g−1 at 0.1, 0.2, 0.5, 1, 2 A g−1, respectively. The battery exhibits a high energy density (249 W h kg−1) and a long-term reversible cycling performance (78.3 % retained at 5 A g−1 after 2000 cycles). The complete morphology of (NH4)2V6O16 after long-term cycle also illustrates its good flexibility during Zn2+ insertion/extraction without structural damage. Multiple analytical measurements methods are applied to investigate the major reaction mechanisms of the Zn2+ reversible (de)intercalation. The results demonstrate that the (NH4)2V6O16 as a cathode substitute is very promising for ARZIBs or other advanced battery systems.

Amorphous Bimetallic Oxides Fe-V-O with Tunable Compositions toward Rechargeable Zn-Ion Batteries with Excellent Low-Temperature Performance.

Vanadium oxides have been considered as promising cathode candidates for zinc-ion batteries (ZIBs) because of their high theoretical specific capacity. However, the poor rate performance and the unsatisfactory cycle life resulting from the sluggish electrode kinetics seriously impede their practical implementation. Herein, we report the rational design of amorphous Fe-V-O bimetallic oxides with tunable compositions as cathodes for aqueous ZIBs. The bimetallic Fe-V-O oxides show improved composition-dependent Zn2+ storage performance and superior structural integrity during cycling. The enhanced electrode kinetics is attributed to the superior electronic conductivity of Fe-V-O oxides than pristine V2O5 owing to the introduction of the Fe element and an amorphous crystalline structure, which can provide reduced diffusion paths and more free volume for Zn2+ insertion. As a result, the as-prepared Fe-V-O exhibits outstanding rate capability and impressive cycling stability. Particularly, a stable reversible capacity of 70 mA h g-1 can be still maintained after 2500 cycles at 5 A g-1, corresponding to the high capacity retention of 95%.

Boosting aqueous zinc-ion storage in MoS2 via controllable phase

Recently, aqueous rechargeable Zn-ion batteries have attracted extensive attention, owing to their low-cost, high operational safety and environmental friendliness. However, the aqueous zinc-ion battery is still in a very infant stage, and the main challenge is to develop the ideal cathode due to the sluggish kinetics and low reversibility of divalent zinc ions. Herein, for the first time, we report controllable phase engineered few-layered MoS2 nanosheet as cathode materials for rechargeable aqueous Zn-ion batteries and systematically study their performance. We found that the obtained MoS2 with different phase contents showed distinct performance in the rechargeable aqueous zinc-ion battery. In particular, the MoS2 nanosheets with ~70% 1T phase content displays excellent specific capacity and shows outstanding long-term cyclic stability. The mechanisms involved were clarified by not only comprehensive characterizations, but also the density functional theory (DFT) simulations that reveal the 1T phase MoS2 has much lower Zn diffusion energy barriers. This study provides new insight into the effect of different phases on the performance of MoS2-based electrodes and will improve our understanding of developing better cathodes for the aqueous rechargeable Zn-ion batteries.

Fast Zn2+ kinetics of vanadium oxide nanotubes in high-performance rechargeable zinc-ion batteries

Mild aqueous rechargeable Zn-ion batteries emerge as potential grid energy storage devices due to excellent cycling stability, high Coulombic efficiency and low cost. However, reliable cathodes with high rate capability still need to be optimized. Previous vanadium oxide cathodes generally show the mechanism of Zn2+ intercalation into crystal layers, during which the lattice structure of active materials keeps stable. Different from this intercalation mechanism, here, we report a special conversion mechanism of Zn2+ storage. Vanadium oxide nanotubes with interlaminar dodecylamine are employed as the cathode. During the initial activation process, the cathode is fully converted to layered zinc pyrovanadate with amorphous zones induced by protonated dodecylamine, while the discharge process results in reversible formation of an amorphous-phase product during cycling. Layered zinc pyrovanadate can be electrochemically recovered from the amorphous phase after the Zn2+ de-intercalation. Despite an armorphous phase as the discharge product, this active material shows high cycling stability and fast Zn2+ kinetics. In addition, this cathode displays a specific energy density of ~242.5 Wh kg−1 and shows capacity retention of 80.5% after 950 cycles at 2.4 A g−1. Even at a high current density of 9.6 A g−1, the cathode delivers a specific energy of ~50 Wh kg−1 (5460 W kg−1) in 33 s. Although vanadium oxide nanotubes with interlaminar dodecylamine ions show little success in Li/Na-ion batteries with non-aqueous electrolytes, a mild aqueous Zn-ion system rejuvenates this material.

A flexible, electrochromic, rechargeable Zn-ion battery based on actiniae-like self-doped polyaniline cathode

A flexible, electrochromic, rechargeable Zn-ion battery, with a monitoring function of the energy storage according to color variation, has been prepared and characterized.

Rechargeable Zn-ion batteries with high power and energy densities: a two-electron reaction pathway in birnessite MnO2 cathode materials

As one of the most promising next-generation safe and green energy storage technologies, aqueous Zn-ion batteries have attracted considerable attention in recent years.

A single-ion conducting covalent organic framework for aqueous rechargeable Zn-ion batteries.

Despite their potential as promising alternatives to current state-of-the-art lithium-ion batteries, aqueous rechargeable Zn-ion batteries are still far away from practical applications. Here, we present a new class of single-ion conducting electrolytes based on a zinc sulfonated covalent organic framework (TpPa-SO3Zn0.5) to address this challenging issue. TpPa-SO3Zn0.5 is synthesised to exhibit single Zn2+ conduction behaviour via its delocalised sulfonates that are covalently tethered to directional pores and achieve structural robustness by its β-ketoenamine linkages. Driven by these structural and physicochemical features, TpPa-SO3Zn0.5 improves the redox reliability of the Zn metal anode and acts as an ionomeric buffer layer for stabilising the MnO2 cathode. Such improvements in the TpPa-SO3Zn0.5–electrode interfaces, along with the ion transport phenomena, enable aqueous Zn–MnO2 batteries to exhibit long-term cyclability, demonstrating the viability of COF-mediated electrolytes for Zn-ion batteries.

In situ grown 2D hydrated ammonium vanadate nanosheets on carbon cloth as a free-standing cathode for high-performance rechargeable Zn-ion batteries

Ultrathin 2D ammonium vanadate nanosheets were grown on alkali-treated carbon cloth via a facile hydrothermal method. This free-standing cathode enables fast ion/electronic transport and reduces the aggregation of ultrathin ammonium vanadate nanosheets.

Porous hydrated ammonium vanadate as a novel cathode for aqueous rechargeable Zn-ion batteries.

Development of suitable cathodes for use in aqueous rechargeable zinc ion batteries has attracted extensive interest. Herein, the electrochemical and structural changes of a novel porous hydrated ammonium vanadate (AVO) cathode in an aqueous ZnSO4-based electrolyte are reported. The AVO/Zn system exhibits a high reversible capacity of 418 mA h g-1, excellent long-term cyclability, and outstanding storage performance. Moreover, an interesting insertion mechanism with ternary carriers in a Zn/AVO aqueous rechargeable zinc-ion battery has been demonstrated for the first time.

A high-power and long-life aqueous rechargeable Zn-ion battery based on hierarchically porous sodium vanadate.

Recently, there has been renewed interest in aqueous Zn-ion batteries. Here, electrochemical and structural changes of hierarchically porous sodium vanadate (NVO) in aqueous Zn-ion batteries are demonstrated. The hierarchically porous NVO cathode exhibits a high power density of 7139 W h kg-1 at 10 A g-1 and excellent long-term cyclability. Moreover, the consequent capacitive- and diffusion-controlled mechanism in Zn/NVO battery chemistry has been first reported. Such a hybrid control mechanism may certainly trigger new opportunities in the rapid development of Zn-ion batteries.

Facile hydrothermal synthesis and electrochemical properties of (NH4)2V10O25·8H2O nanobelts for high-performance aqueous zinc ion batteries

Aqueous rechargeable Zn-ion batteries (ARZIBs) are highly desirable for grid-scale applications because of their high safety, low cost, sustainability, and environmental friendliness. However, the lack of suitable cathode materials possessing satisfactory cycle performance and energy density limits their wide applications. In this work, (NH4)2V10O25·8H2O nanobelts, the ammonium ion, and water expanded VO skeletons, are synthesized by a facile hydrothermal synthesis and reported as a cathode material in ARZIBs. The Zn//(NH4)2V10O25·8H2O nanobelts battery achieves capacities as high as 417, 366, 322, 268 and 209 mA h g−1 at 0.1, 0.2, 0.5, 1.0 and 2.0 A g−1 respectively, showing high rate capacity. In addition, the battery not only exhibits an excellent cycle lifespan of 310 mA h g−1 after 100 cycles (0.1 A g−1), but delivers a high energy density of 320 Wh kg−1 at the power density of 77 W kg−1. These results demonstrate that the Zn//(NH4)2V10O25·8H2O nanobelts battery possesses significantly enhanced electrochemical performances, which is superior to most state-of-the-art cathode materials for ARZIBs. Furthermore, the reaction mechanism of the reversible Zn2+ intercalation/deintercalation into (NH4)2V10O25·8H2O is studied by multiple analytical methods. This work not only demonstrates that (NH4)2V10O25·8H2O nanobelts can act as a promising cathode candidate, but also provides an attractive solution for the synthesis of cathode materials for ARZIBs and other multivalent metal-ion batteries.

Ammonium Vanadium Oxide [(NH4)2V4O9] Sheets for High Capacity Electrodes in Aqueous Zinc Ion Batteries

Aqueous rechargeable Zn-ion batteries (ARZIBs) are being extensively investigated for large scale energy storage applications owing to their high safety, low cost, and environmental friendliness. I...