With the rapid development of wearable and portable electronics, flexible and stretchable energy storage devices to power them are rapidly emerging. Among numerous flexible energy storage ...technologies, flexible batteries are considered as the most favorable candidate due to their high energy density and long cycle life. In particular, flexible 1D batteries with the unique advantages of miniaturization, adaptability, and weavability are expected to be a part of such applications. The development of 1D batteries, including lithium‐ion batteries, zinc‐ion batteries, zinc–air batteries, and lithium–air batteries, is comprehensively summarized, with particular emphasis on electrode preparation, battery design, and battery properties. In addition, the remaining challenges to the commercialization of current 1D batteries and prospective opportunities in the field are discussed.
The latest advances in flexible 1D batteries, including metal‐ion batteries and metal–air batteries, are summarized, with particular emphasis on electrode preparation, battery design, and electrochemical and mechanical properties. Additionally, future perspectives on and remaining challenges to the practical application of 1D batteries are also discussed to promote the commercialization of 1D batteries.
The lithium (Li)–air battery has an ultrahigh theoretical specific energy, however, even in pure oxygen (O2), the vulnerability of conventional organic electrolytes and carbon cathodes towards ...reaction intermediates, especially O2−, and corrosive oxidation and crack/pulverization of Li metal anode lead to poor cycling stability of the Li‐air battery. Even worse, the water and/or CO2 in air bring parasitic reactions and safety issues. Therefore, applying such systems in open‐air environment is challenging. Herein, contrary to previous assertions, we have found that CO2 can improve the stability of both anode and electrolyte, and a high‐performance rechargeable Li–O2/CO2 battery is developed. The CO2 not only facilitates the in situ formation of a passivated protective Li2CO3 film on the Li anode, but also restrains side reactions involving electrolyte and cathode by capturing O2−. Moreover, the Pd/CNT catalyst in the cathode can extend the battery lifespan by effectively tuning the product morphology and catalyzing the decomposition of Li2CO3. The Li–O2/CO2 battery achieves a full discharge capacity of 6628 mAh g−1 and a long life of 715 cycles, which is even better than those of pure Li–O2 batteries.
CO2 can do: CO2 makes Li–O2 batteries more stable. On the anode side, CO2 can facilitate the formation of a protective and self‐healing Li2CO3 film, which can expel the H2O and aggressive intermediates during cycling. The cathode and electrolyte are also protected because the O2− intermediate is captured by CO2 to prevent the formation of 1O2.
Sodium‐ion batteries (SIBs) are considered as promising alternatives to lithium‐ion batteries (LIBs) for large‐scale electrical‐energy‐storage applications due to the wide availability and the low ...cost of Na resources. Along with the avenues of research on flexible LIBs, flexible SIBs are now being actively developed as one of the most promising power sources for the emerging field of flexible and wearable electronic devices. Here, the recent progress on flexible electrodes based on metal substrates, carbonaceous substrates (i.e., graphene, carbon cloth, and carbon nanofibers), and other materials, as well as their applications in flexible SIBs, are summarized. Also, some future research directions for constructing flexible SIBs are proposed, with the aim of providing inspiration to the further development of advanced flexible SIBs.
Flexible sodium‐ion batteries (SIBs) are being actively developed as one of the most promising power sources for the emerging field of flexible and wearable electronic devices. The recent progress on flexible electrodes based on metal substrates, carbonaceous substrates, and other materials, is summarized, along with their applications in flexible SIBs.
The flexible Li‐O2 battery is suitable to satisfy the requirements of a self‐powered energy system, thanks to environmental friendliness, low cost, and high theoretical energy density. Herein, a ...flexible porous bifunctional electrode with both electrocatalytic and photocatalytic activity was synthesized and introduced as a cathode to assemble a high‐performance Li‐O2 battery that achieved an overpotential of 0.19 V by charging with the aid of solar energy. As a proof‐of‐concept application, a flexible Li‐O2 battery was constructed and integrated with a solar cell via a scalable encapsulate method to fabricate a flexible self‐powered energy system with excellent flexibility and mechanical stability. Moreover, by exploring the evolution of the electrode morphology and discharge products (Li2O2), the charging process of the Li‐O2 battery powered by solar energy and solar cell was demonstrated.
A flexible self‐powered energy system was fabricated by combining a flexible Li‐O2 battery with a flexible solar cell. By exploring the evolution of the electrode morphology and discharge products (Li2O2), the charging process of the Li‐O2 battery powered by solar energy and solar cell is demonstrated.
To promote the development of high energy Li–O2 batteries, it is important to design and construct a suitable and effective oxygen‐breathing cathode. Herein, activated cobalt‐nitrogen‐doped carbon ...nanotube/carbon nanofiber composites (Co‐N‐CNT/CNF) as the effective cathodes for Li–O2 batteries are prepared by in situ chemical vapor deposition (CVD). The unique architecture of these electrodes facilitates the rapid oxygen diffusion and electrolyte penetration. Meanwhile, the nitrogen‐doped carbon nanotube/carbon nanofiber (N‐CNT/CNF) and Co/CoNx serve as reaction sites to promote the formation/decomposition of discharge product. Li–O2 batteries with Co‐N‐CNT/CNF cathodes exhibit superior electrochemical performance in terms of a positive discharge plateau (2.81 V) and a low charge overpotential (0.61 V). Besides, Li–O2 batteries also present a high discharge capacity (11512.4 mAh g−1 at 100 mA g−1), and a long cycle life (130 cycles). Meanwhile, the Co‐N‐CNT/CNF cathode also has an excellent flexibility, thus the assembled flexible battery with Co‐N‐CNT/CNF can work normally and hold a wonderful capacity rate under various bending conditions.
Activated cobalt‐nitrogen‐doped carbon nanotube/carbon nanofiber composites (Co‐N‐CNT/CNF) cathodes are prepared via in situ chemical vapor deposition. The Li–O2 batteries with these cathodes exhibit great performances. Meanwhile, Co‐N‐CNT/CNF cathodes are flexible, based on which the assembled flexible battery exhibits great performances and flexibility under various bending conditions.
With the rising demand for flexible and wearable electronic devices, flexible power sources with high energy densities are required to provide a sustainable energy supply. Theoretically, ...rechargeable, flexible Li‐O2/air batteries can provide extremely high specific energy densities; however, the high costs, complex synthetic methods, and inferior mechanical properties of the available flexible cathodes severely limit their practical applications. Herein, inspired by the structure of human blood capillary tissue, this study demonstrates for the first time the in situ growth of interpenetrative hierarchical N‐doped carbon nanotubes on the surface of stainless‐steel mesh (N‐CNTs@SS) for the fabrication of a self‐supporting, flexible electrode with excellent physicochemical properties via a facile and scalable one‐step strategy. Benefitting from the synergistic effects of the high electronic conductivity and stable 3D interconnected conductive network structure, the Li‐O2 batteries obtained with the N‐CNTs@SS cathode exhibit superior electrochemical performance, including a high specific capacity (9299 mA h g−1 at 500 mA g−1), an excellent rate capability, and an exceptional cycle stability (up to 232 cycles). Furthermore, as‐fabricated flexible Li‐air batteries containing the as‐prepared flexible super‐hydrophobic cathode show excellent mechanical properties, stable electrochemical performance, and superior H2O resistibility, which enhance their potential to power flexible and wearable electronic devices.
Inspired by blood capillary tissue, a self‐standing, flexible N‐CNTs@SS Li‐O2 battery cathode with an interpenetrative structure is fabricated via a facile and scalable one‐step strategy. The flexible Li‐O2 batteries with N‐CNTs@SS exhibit excellent mechanical properties, stable electrochemical performance, and superior H2O resistibility.
Autonomous underwater vehicles (AUVs) are submersible underwater vehicles controlled by onboard computers. AUV formation is a cooperative control which focuses on controlling multiple AUVs to move in ...a group while executing tasks. In contrast to a single AUV, multi-AUV formation represents higher efficiency and better stability for many applications, such as oil and gas industries, hydrographic surveys, and military missions, etc. To achieve better formation, there are several key factors, including AUV performance, formation control, and communication capability. However, most studies in the field of AUV formation mainly focus on formation control methods. We observe that the research of communication capability and AUV performance of multiple AUV formation is still in an early stage. It is beneficial to researchers to present a comprehensive survey of the state of the art of AUV formation research and development. In this paper, we study AUV, formation control, and underwater acoustic communication capability in detail. We propose a classification framework with three dimensions, including AUV performance, formation control, and communication capability. This framework provides a comprehensive classification method for future AUV formation research. It also can be used to compare different methods and help engineers choose suitable formation methods for various applications. Moreover, our survey discusses formation architecture with communication constraints and we identify some common misconceptions and questionable research for formation control related to communication.
Increasing energy density of Li-ion batteries (LiBs) along with fast charging capability are two key approaches to eliminate range anxiety and boost mainstream adoption of electric vehicles (EVs). ...Either the increase of energy density or of charge rate, however, heightens the risk of lithium plating and thus deteriorates cell life. The trilemma of fast charging, energy density and cycle life are studied systematically in this work utilizing a physics-based aging model with incorporation of both lithium plating and solid-electrolyte-interphase (SEI) growth. The model is able to capture the key feature of temperature-dependent aging behavior of LiBs, or more specifically, the existence of an optimal temperature with the longest cycle life. We demonstrate that this optimal temperature is a result of competition between SEI growth and lithium plating. Further, it is revealed that either the increase of charge rate or of energy density accelerates lithium plating induced aging. As such, the optimal temperature for cell life increases from ∼20 °C for a high-power cell at 1C charge to ∼35–45 °C with the increase of charge rate and/or energy density. It would be beneficial to further increase the charge temperature in order to enable robust fast charging of high energy EV cells.
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•Temperature-dependent aging behavior of Li-ion battery is studied numerically.•Overall aging rate depends on the competition of lithium plating and SEI growth.•The optimal temperature for cycle life increases with charge rate & energy density.•Raising charging temperature is an effective method to eliminating lithium plating.
With the rising development of flexible and wearable electronics, corresponding flexible energy storage devices with high energy density are required to provide a sustainable energy supply. ...Theoretically, rechargeable flexible Li–O2 batteries can provide high specific energy density; however, there are only a few reports on the construction of flexible Li–O2 batteries. Conventional flexible Li–O2 batteries possess a loose battery structure, which prevents flexibility and stability. The low mechanical strength of the gas diffusion layer and anode also lead to a flexible Li–O2 battery with poor mechanical properties. All these attributes limit their practical applications. Herein, the authors develop an integrated flexible Li–O2 battery based on a high‐fatigue‐resistance anode and a novel flexible stretchable gas diffusion layer. Owing to the synergistic effect of the stable electrocatalytic activity and hierarchical 3D interconnected network structure of the free‐standing cathode, the obtained flexible Li–O2 batteries exhibit superior electrochemical performance, including a high specific capacity, an excellent rate capability, and exceptional cycle stability. Furthermore, benefitting from the above advantages, the as‐fabricated flexible batteries can realize excellent mechanical and electrochemical stability. Even after a thousand cycles of the bending process, the flexible Li–O2 battery can still possess a stable open‐circuit voltage, a high specific capacity, and a durable cycle performance.
A novel integrated self‐package flexible Li–O2 battery is developed with a stable composite anode and flexible gas diffusion layer. Excellent mechanical stability and superior battery performances are successfully achieved under different shapes and even after repeated mechanical twisting, bending processes, showing high promise to power next generation versatile flexible electronics.
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