Xiao- Yang

Flexible and Foldable Li–O2 Battery Based on Paper-Ink Cathode

A flexible freestanding air cathode inspired by traditional Chinese calligraphy art is built. When this novel electrode is employed as both a new concept cathode and current collector, to replace conventional rigid and bulky counterparts, a highly flexible and foldable Li-O2 battery with excellent mechanical strength and superior electrochemical performance is obtained.

Flexible Electrodes for Sodium-Ion Batteries: Recent Progress and Perspectives

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.

High-Performance Integrated Self-Package Flexible Li–O2 Battery Based on Stable Composite Anode and Flexible Gas Diffusion Layer

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 Water-/Fireproof Flexible Lithium–Oxygen Battery Achieved by Synergy of Novel Architecture and Multifunctional Separator

To meet the increasing demands for portable and flexible devices in a rapidly developing society, it is urgently required to develop highly safe and flexible electrochemical energy-storage systems. Flexible lithium-oxygen batteries with high theoretical specific energy density are promising candidates; however, the conventional half-open structure design prevents it from working properly under water or fire conditions. Herein, as a proof-of-concept experiment, a highly safe flexible lithium-oxygen battery achieved by the synergy of a vital multifunctional structure design and a unique composite separator is proposed and fabricated. The structure can effectively prevent the invasion of water from the environment and combustion, which is further significantly consolidated with the help of a polyimide and poly(vinylidene fluoride-co-hexafluoropropylene) composite separator, which holds good water resistance, thermal stability, and ionic conductivity. Unexpectedly, the obtained lithium-oxygen battery exhibits superior flexibility, water resistance, thermal resistance, and cycling stability (up to 218 cycles; at a high current of 1 mA and capacity of 4 mA h). This novel water/fireproof, flexible lithium-oxygen battery is a promising candidate to power underwater flexible electronics.

CeO 2 @NiCo 2 O 4 nanowire arrays on carbon textiles as high performance cathode for Li-O 2 batteries

The successful development of Li-O2 battery technology depends on developing a stable and efficient cathode. As an important step toward this goal, for the first time, we report the development of CeO2 nanoparticles modified NiCo2O4 nanowire arrays (NWAs) grown on the carbon textiles as a new carbon-free and binder-free cathode system. In this study, the Li-O2 battery with the CeO2@NiCo2O4 NWAs has exhibited much reduced overpotentials, a high discharge capacity, an improved cycling stability, outperforming the Li-O2 battery with NiCo2O4 NWAs. These improvements can be attributed to both the tailored morphology of discharge product and improved oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activity after CeO2 NPs deposition. To a considerable extent, this idea of cathode construction including structure design and composition optimization can provide guidance for further researches in developing more powerful cathode for Li-O2 battery.

Composition-tunable synthesis of “clean” syngas via a one-step synthesis of metal-free pyridinic-N-enriched self-supported CNTs: the synergy of electrocatalyst pyrolysis temperature and potential

Exploring efficient and environmentally friendly ways for producing clean syngas is of great significance for realizing an artificial carbon cycle associated with clean and renewable energy. Herein, as a proof-of-concept experiment, we controllably synthesized syngas via electroreduction of CO2 using an integrated 3D electrode as the catalyst. An efficient electrode was synthesized in only one step and immediately used for electroreduction of CO2 to CO with a low overpotential. Moreover, pyridinic-N predominated in the synthesized N-CNTs, followed by graphitic-N, both of which were demonstrated to supply the active nitrogen defects for the CO2 conversion. Impressively, by tuning the pyrolysis temperature or applied potential, we were able to easily tailor the H2/CO ratio in the clean syngas products in a large range between 1 : 3 and 3 : 1. This ability to tailor the H2/CO ratio has important applications in industrial production.

Hybrid electrolyte with robust garnet-ceramic electrolyte for lithium anode protection in lithium-oxygen batteries

Rechargeable lithium-oxygen (Li-O2) batteries have received intensive research interest due to its ultrahigh energy density, while its cycle stability is still hindered by the high reactivity of the Li anode with oxygen and moisture. To alleviate the corrosion of the metallic lithium anodes for achieving a stable Li-O2 battery, and as a proof-of-concept experiment, a distinctive hybrid electrolyte system with an organic/ceramic/organic electrolyte (OCOE) architecture is designed. Importantly, the cycle number of Li-O2 batteries with OCOE is significantly improved compared with batteries with an organic electrolyte (OE). This might be attributed to the effective suppression of the lithium anode corrosion caused by the OE degradation and the crossover of oxygen from the cathode. We consider that our facile, low-cost, and highly effective lithium protection strategy presents a new avenue to address the daunting corrosion problem of lithium metal anodes in Li-O2 batteries. In addition, the proposed strategy can be easily extended to other metal-O2 battery systems, such as Na-O2 batteries.

In Situ CVD Derived Co-N-C Composite as Highly Efficient Cathode for Flexible Li-O2 Batteries

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.