Owing to the development of aqueous rechargeable zinc‐ion batteries (ZIBs), flexible ZIBs are deemed as potential candidates to power wearable electronics. ZIBs with solid‐state polymer electrolytes ...can not only maintain additional load‐bearing properties, but exhibit enhanced electrochemical properties by preventing dendrite formation and inhibiting cathode dissolution. Substantial efforts have been applied to polymer electrolytes by developing solid polymer electrolytes, hydrogel polymer electrolytes, and hybrid polymer electrolytes; however, the research of polymer electrolytes for ZIBs is still immature. Herein, the recent progress in polymer electrolytes is summarized by category for flexible ZIBs, especially hydrogel electrolytes, including their synthesis and characterization. Aiming to provide an insight from lab research to commercialization, the relevant challenges, device configurations, and life cycle analysis are consolidated. As flexible batteries, the majority of polymer electrolytes exploited so far only emphasizes the electrochemical performance but the mechanical behavior and interactions with the electrode materials have hardly been considered. Hence, strategies of combining softness and strength and the integration with electrodes are discussed for flexible ZIBs. A ranking index, combining both electrochemical and mechanical properties, is introduced. Future research directions are also covered to guide research toward the commercialization of flexible ZIBs.
An insight from lab research to commercialization for flexible zinc‐ion batteries is provided by comprehensively reviewing the development of polymer electrolytes, relevant challenges and strategies, and device configurations. Aiming to quantify the feasibility for commercialization, a ranking index is proposed combining both electrochemical and mechanical properties. Future research directions are also covered to guide research toward commercialization.
Highlights
A triple functional additive with a trace amount (1 mM) was proposed to protect Zn anodes.
The additive lowers the hydrogen evolution reaction potential, encourages the formation of an in ...situ solid electrolyte interphase and shields the “tip effect”
Dendrite free Zn deposition and highly reversible Zn plating/stripping behaviors were realized by the triple protections
Although their cost-effectiveness and intrinsic safety, aqueous zinc-ion batteries suffer from notorious side reactions including hydrogen evolution reaction, Zn corrosion and passivation, and Zn dendrite formation on the anode. Despite numerous strategies to alleviate these side reactions have been demonstrated, they can only provide limited performance improvement from a single aspect. Herein, a triple-functional additive with trace amounts, ammonium hydroxide, was demonstrated to comprehensively protect zinc anodes. The results show that the shift of electrolyte pH from 4.1 to 5.2 lowers the HER potential and encourages the in situ formation of a uniform ZHS-based solid electrolyte interphase on Zn anodes. Moreover, cationic NH
4+
can preferentially adsorb on the Zn anode surface to shield the “tip effect” and homogenize the electric field. Benefitting from this comprehensive protection, dendrite-free Zn deposition and highly reversible Zn plating/stripping behaviors were realized. Besides, improved electrochemical performances can also be achieved in Zn//MnO
2
full cells by taking the advantages of this triple-functional additive. This work provides a new strategy for stabilizing Zn anodes from a comprehensive perspective.
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•Ultrasonic stimulation enhances battery safety and performance.•A chemistry-agnostic method for battery dendrite suppression.•Acoustic streaming enables rapid charging above the ...limiting rate.
This research introduces a chemistry-agnostic approach to achieve rapid and degradation-free battery charging via ultrasonic agitation. An ultrasonic device operating in the megahertz range was used to stimulate electrolyte flow from outside the cell. The acoustic streaming effect accelerates ion transport from the bulk electrolyte to the electrode surface and suppresses the formation of an ion depletion zone. An experimental setup was used to optically observe the formation of dendrites when the current imposed across two zinc electrodes exceeded the limiting current. Beyond this limit, diffusion alone cannot provide sufficient ions, resulting in an ion depletion zone. It was subsequently shown that dendrite formation was reduced by over 98% when 15x the limiting current was forced across the electrodes and acoustic stimulation was delivered. Furthermore, it was shown that compared to the scenario without ultrasonic stimulation, the steady state potential was also reduced by 29%, indicating much better ion exchange between the electrodes. These findings suggest that ultrasonic stimulation can be a tool for enhancing electrochemical processes such as battery charging and discharging.
Abstract
The paper discusses the challenges associated with the performance of zinc‐ion batteries (ZIBs), such as side reactions that lead to reduced capacity and lifespan. The strategies for ...mitigating side reactions in ZIBs, including additives, electrolyte‐electrode interface modification, and electrolyte composition optimization, are explored. Combinations of these approaches may be necessary to achieve the best performance for ZIBs. However, continued research is needed to improve the commercial viability of ZIBs. Areas of research requiring attention include the understanding of the mechanisms behind side reactions in ZIBs and the development of cost‐effective and scalable manufacturing processes for ZIBs with available electrolyte. By developing effective strategies for mitigating side reactions, researchers can improve the efficiency and lifespan of ZIBs, making them more competitive with lithium‐ion batteries in various applications, including grid energy storage.
Vanadium bronzes have been well-demonstrated as promising cathode materials for aqueous zinc-ion batteries. However, conventional single-ion pre-intercalated V
2
O
5
nearly reached its energy/power ...ceiling due to the nature of micro/electronic structures and unfavourable phase transition during Zn
2+
storage processes. Here, a simple and universal
in-situ
anodic oxidation method of quasi-layered CaV
4
O
9
in a tailored electrolyte was developed to introduce dual ions (Ca
2+
and Zn
2+
) into bilayer δ-V
2
O
5
frameworks forming crystallographic ultra-thin vanadium bronzes, Ca
0.12
Zn
0.12
V
2
O
5
·
n
H
2
O. The materials deliver transcendental maximum energy and power densities of 366 W h kg
−1
(478 mA h g
−1
@ 0.2 A g
−1
) and 6627 W kg
−1
(245 mA h g
−1
@ 10 A g
−1
), respectively, and the long cycling stability with a high specific capacity up to 205 mA h g
−1
after 3000 cycles at 10 A g
−1
. The synergistic contributions of dual ions and Ca
2+
electrolyte additives on battery performances were systematically investigated by multiple
in-/ex-situ
characterisations to reveal reversible structural/chemical evolutions and enhanced electrochemical kinetics, highlighting the significance of electrolyte-governed conversion reaction process. Through the computational approach, reinforced “pillar” effects, charge screening effects and regulated electronic structures derived from pre-intercalated dual ions were elucidated for contributing to boosted charge storage properties.
The paper discusses the progress and commercialization of binders for energy storage applications, such as batteries. It explains the role of binders in holding together active materials and current ...collectors, and highlights the challenges associated with conventional organic solvents in binders. The potential of aqueous binders is introduced as a cost-effective and environmentally friendly alternative. The advantages and limitations of different types of binders are discussed, and the importance of binder selection for optimal battery performance is emphasized. The current state of commercialization of binders is reviewed, and the need for collaboration between researchers, manufacturers, and policymakers to develop and promote environmentally friendly and cost-effective binders is emphasized. The paper concludes by outlining future directions for research and development to further improve the performance and commercialization of binders, while addressing limitations such as lack of standardization, high cost, and long-term stability and reliability.
Zinc‐ion batteries (ZIBs), which are inexpensive and environmentally friendly, have a lot of potential for use in grid‐scale energy storage systems, but their use is constrained by the availability ...of suitable cathode materials. MnO2‐based cathodes are emerging as a promising contenders, due to the great availability and safety, as well as the device's stable output voltage platform (1.5 V). Improving the slow kinetics of MnO2‐based cathodes caused by low electrical conductivity and mass diffusion rate is a challenge for their future use in next‐generation rapid charging devices. Herein, the aforementioned challenges are overcome by proposing a sodium‐intercalated manganese oxide (NMO) with 3D varying thinness carbon nanotubes (VTCNTs) networks as appropriate free‐standing, binder‐free cathodes (NMO/VTCNTs) without any heat treatment. A network construction strategy based on CNTs of different diameters is proposed for the first time to provide high specific capacity while achieving high mass loading. The specific capacity of as‐prepared cathodes is significantly increased. The resulting free‐standing binder‐free cathodes achieve excellent capacity (329 mAh g−1 after 120 cycles at 0.2 A g−1 and 225 mAh g−1 after 200 cycles at 1 A g−1) and long‐term cycling stability (158 mAh g−1 at 2 A g−1 after 1000 cycles).
Herein, carbon nanotube (CNT) networks to support manganese‐based materials are prepared as an appropriate free‐standing, binder‐free cathode (sodium‐intercalated manganese oxide NMO/VTCNTs) for aqueous Zn‐ion batteries. The suitable structures overcome the slow reaction kinetics and improve the mass loading for practical cathode use.
Due to their potential for high energy density, low cost, and environmental sustainability, zinc-ion batteries (ZIBs) have emerged as a promising energy storage technology. The performance, safety, ...and overall efficiency of ZIBs are significantly impacted by the properties of the electrolyte, such as ionic conductivity, electrochemical stability window, viscosity, and compatibility with other battery components. The use of ionic liquids (ILs) in ZIBs has gained extensive attention in recent years due to their desirable properties, such as high thermal stability, low volatility, wide electrochemical window, and tunable physicochemical properties. Therefore, this paper provides a bibliometric analysis of recent advances in the use of ILs as electrolytes in ZIBs. Current research trends, authorship patterns, and publications of ILs in ZIBs are analyzed. Our review reveals a growing interest in the use of ILs as electrolytes in ZIBs, and the development of novel ILs with tailored properties to meet the specific requirements of ZIBs is of a specific focus. This paper provides insights into the recent advancements and future research directions in the field of ILs as electrolytes for ZIBs.
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•A comprehensive overview of the development of zinc-ion batteries (ZIBs) is provided.•A collaborative analysis between countries and universities in ZIBs is conducted.•Key challenges faced in the electrolytes of ZIBs are presented.•The opportunities of using ionic liquids in ZIBs are discussed.
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