An acid-assisted vacuum filtration approach towards flexible PDI/SWCNT cathodes for highly stable organic lithium ion batteries

Carbonyl Chemistry for Advanced Electrochemical Energy Storage Systems

On the basis of the sustainable concept, organic compounds and carbon materials both mainly composed of light C element have been regarded as powerful candidates for advanced electrochemical energy storage (EES) systems, due to theie merits of low cost, eco-friendliness, renewability, and structural versatility. It is investigated that the carbonyl functionality as the most common constituent part serves a crucial role, which manifests respective different mechanisms in the various aspects of EES systems. Notably, a systematical review about the concept and progress for carbonyl chemistry is beneficial for ensuring in-depth comprehending of carbonyl functionality. Hence, a comprehensive review about carbonyl chemistry has been summarized based on state-of-the-art developments. Moreover, the working principles and fundamental properties of the carbonyl unit have been discussed, which has been generalized in three aspects, including redox activity, the interaction effect, and compensation characteristic. Meanwhile, the pivotal characterization technologies have also been illustrated for purposefully studying the related structure, redox mechanism, and electrochemical performance to profitably understand the carbonyl chemistry. Finally, the current challenges and promising directions are concluded, aiming to afford significant guidance for the optimal utilization of carbonyl moiety and propel practicality in EES systems.

Biomass-Derived Flexible Carbon Architectures as Self-Supporting Electrodes for Energy Storage

With the swift advancement of the wearable electronic devices industry, the energy storage components of these devices must possess the capability to maintain stable mechanical and chemical properties after undergoing multiple bending or tensile deformations. This circumstance has expedited research efforts toward novel electrode materials for flexible energy storage devices. Nonetheless, among the numerous materials investigated to date, the incorporation of metal current collectors or insulative adhesives remains requisite, which entails additional costs, unnecessary weight, and high contact resistance. At present, biomass-derived flexible architectures stand out as a promising choice in electrochemical energy device applications. Flexible self-supporting properties impart a heightened mechanical performance, obviating the need for additional binders and lowering the contact resistance. Renewable, earth-abundant biomass endows these materials with cost-effectiveness, diversity, and modulable chemical properties. To fully exploit the application potential in biomass-derived flexible carbon architectures, understanding the latest advancements and the comprehensive foundation behind their synthesis assumes significance. This review delves into the comprehensive analysis of biomass feedstocks and methods employed in the synthesis of flexible self-supporting carbon electrodes. Subsequently, the advancements in their application in energy storage devices are elucidated. Finally, an outlook on the potential of flexible carbon architectures and the challenges they face is provided.

Solution-processed perylene diimide-ethylene diamine cathodes for aqueous zinc ion batteries

Organic electroactive compounds can be applied as alternative cathodes in rechargeable zinc ion batteries (ZIBs) instead of using inorganic cathode materials with low stability or high toxicity. However, many reported organic ZIB cathodes have some limitations, which are their tedious synthesis processes and low yields. In this work, perylene diimide-ethylenediamine/carbon black (PDI-EDA/CB) composites are prepared with a high yield of over 88% under mild conditions via a solution-based processing method. As the organic cathodes in aqueous ZIBs, the PDI-EDA/CB composites have a high specific capacity of 118.0 mA h g^-1 at 0.05 A g^-1; this capacity can be maintained as 95.0 mA h g^-1 even at a high current density of 5.00 A g^-1. Also, PDI-EDA/CB has good cycling stability by reserving 70.5% of its initial capacity after 1500 charge-discharge cycles at 1.00 A g^-1, outperforming many recently reported ZIB cathodes. As disclosed by the structural and electrochemical characterization of PDI-EDA/CB, its excellent electrochemical performance is due to the zinc ion storage mechanism of PDI-EDA and the solution-based fabrication method.

Review on carbonaceous materials and metal composites in deformable electrodes for flexible lithium-ion batteries

With the rapid propagation of flexible electronic devices, flexible lithium-ion batteries (FLIBs) are emerging as the most promising energy supplier among all of the energy storage devices owing to their high energy and power densities with good cycling stability. As a key component of FLIBs, to date, researchers have tried to develop newly designed high-performance electrochemically and mechanically stable pliable electrodes. To synthesize better quality flexible electrodes, based on high conductivity and mechanical strength of carbonaceous materials and metals, several research studies have been conducted. Despite both materials-based electrodes demonstrating excellent electrochemical and mechanical performances in the laboratory experimental process, they cannot meet the expected demands of stable flexible electrodes with high energy density. After all, various significant issues associated with them need to be overcome, for instance, poor electrochemical performance, the rapid decay of the electrode architecture during deformation, and complicated as well as costly production processes thus limiting their expansive applications. Herein, the recent progression in the exploration of carbonaceous materials and metals based flexible electrode materials are summarized and discussed, with special focus on determining their relative electrochemical performance and structural stability based on recent advancement. Major factors for the future advancement of FLIBs in this field are also discussed.