Dispersion-Assembly Approach to Synthesize Three-Dimensional Graphene/Polymer Composite Aerogel as a Powerful Organic Cathode for Rechargeable Li and Na Batteries

A Comprehensive Compilation of Graphene/Fullerene Polymer Nanocomposites for Electrochemical Energy Storage

Electricity consumption is an integral part of life on earth. Energy generation has become a critical topic, addressing the need to fuel the energy demands of consumers. Energy storage is an offshoot of the mainstream process, which is now becoming a prime topic of research and development. Electrochemical energy storage is an attractive option, serving its purpose through fuel cells, batteries and supercapacitors manipulating the properties of various materials, nanomaterials and polymer substrates. The following review presents a comprehensive report on the use of carbon-based polymer nanocomposites, specifically graphene and fullerene-based polymer nanocomposites, towards electrochemical energy storage. The achievements in these areas, and the types of polymer nanocomposites used are listed. The areas that lack of clarity and have a dearth of information are highlighted. Directions for future research are presented and recommendations for fully utilizing the benefits of the graphene/fullerene polymer nanocomposite system are proposed.

Poly(Anthraquinonyl Sulfide)/CNT Composites as High-Rate-Performance Cathodes for Nonaqueous Rechargeable Calcium-Ion Batteries

Calcium-ion batteries (CIBs) are considered as promising alternatives in large-scale energy storage due to their divalent electron redox properties, low cost, and high volumetric/gravimetric capacity. However, the high charge density of Ca²⁺ contributes to strong electrostatic interaction between divalent Ca²⁺ and hosting lattice, leading to sluggish kinetics and poor rate performance. Here, in situ formed poly(anthraquinonyl sulfide) (PAQS)@CNT composite is reported as nonaqueous calcium-ion battery cathode. The enolization redox chemistry of organics has fast redox kinetics, and the introduction of carbon nanotube (CNT) accelerates electron transportation, which contributes to fast ionic diffusion. As the conductivity of the PAQS is enhanced by the increasing content of CNT, the voltage gap is significantly reduced. The PAQS@CNT electrode exhibits specific capacity (116 mAh g^-1 at 0.05 A g^-1 ), high rate capacity (60 mAh g^-1 at 4 A g^-1 ), and an initial capacity of 82 mAh g^-1 at 1 A g^-1 (83% capacity retention after 500 cycles). The electrochemical mechanism is proved to be that the PAQS undergoes reduction reaction of their carbonyl bond during discharge and becomes coordinated by Ca²⁺ and Ca(TFSI)⁺ species. Computational simulation also suggests that the construction of Ca²⁺ and Ca(TFSI)⁺ co-intercalation in the PAQS is the most reasonable pathway.

3D Carbon Networks: Design and Applications in Sodium Ion Batteries

As the key component of a new generation for low-cost energy storage systems, sodium-ion batteries (SIBs) have attracted enormous attention and research due to its promising potentiality in large-scale electrochemical energy storage. For practical application of SIBs, carbonaceous materials have been considered to be one of the best choices for electrodes in virtue of their abundant reserves, low cost, easy availability, and environmental friendliness. 3D carbon network (3D-carbon) is of particular interests, which has displayed outstanding features, including abundant active sites, interconnected multi-level pore structures, high electronic conductivity, and excellent mechanical stability. Herein, we review the structural advantages of 3D-carbon and its preparation methods, and then discuss recent progress in 3D carbon materials and their composites for SIBs. The superior functionalities of 3D-carbon are emphasized as support templates or encapsulation shell membranes. Finally, we summarize and outline the challenges and future prospects of 3D-carbon in SIBs.

Molecular Design Strategies for Electrochemical Behavior of Aromatic Carbonyl Compounds in Organic and Aqueous Electrolytes

To sustainably satisfy the growing demand for energy, organic carbonyl compounds (OCCs) are being widely studied as electrode active materials for batteries owing to their high capacity, flexible structure, low cost, environmental friendliness, renewability, and universal applicability. However, their high solubility in electrolytes, limited active sites, and low conductivity are obstacles in increasing their usage. Here, the nucleophilic addition reaction of aromatic carbonyl compounds (ACCs) is first used to explain the electrochemical behavior of carbonyl compounds during charge-discharge, and the relationship of the molecular structure and electrochemical properties of ACCs are discussed. Strategies for molecular structure modifications to improve the performance of ACCs, i.e., the capacity density, cycle life, rate performance, and voltage of the discharge platform, are also elaborated. ACCs, as electrode active materials in aqueous solutions, will become a future research hotspot. ACCs will inevitably become sustainable green materials for batteries with high capacity density and high power density.

Recent Progress on Organic Electrodes Materials for Rechargeable Batteries and Supercapacitors

Rechargeable batteries are essential elements for many applications, ranging from portable use up to electric vehicles. Among them, lithium-ion batteries have taken an increasing importance in the day life. However, they suffer of several limitations: safety concerns and risks of thermal runaway, cost, and high carbon footprint, starting with the extraction of the transition metals in ores with low metal content. These limitations were the motivation for an intensive research to replace the inorganic electrodes by organic electrodes. Subsequently, the disadvantages that are mentioned above are overcome, but are replaced by new ones, including the solubility of the organic molecules in the electrolytes and lower operational voltage. However, recent progress has been made. The lower voltage, even though it is partly compensated by a larger capacity density, may preclude the use of organic electrodes for electric vehicles, but the very long cycling lives and the fast kinetics reached recently suggest their use in grid storage and regulation, and possibly in hybrid electric vehicles (HEVs). The purpose of this work is to review the different results and strategies that are currently being used to obtain organic electrodes that make them competitive with lithium-ion batteries for such applications.

Nanomaterials in Advanced, High-Performance Aerogel Composites: A Review

Aerogels are one of the most interesting materials of the 21st century owing to their high porosity, low density, and large available surface area. Historically, aerogels have been used for highly efficient insulation and niche applications, such as interstellar particle capture. Recently, aerogels have made their way into the composite universe. By coupling nanomaterial with a variety of matrix materials, lightweight, high-performance composite aerogels have been developed for applications ranging from lithium-ion batteries to tissue engineering materials. In this paper, the current status of aerogel composites based on nanomaterials is reviewed and their application in environmental remediation, energy storage, controlled drug delivery, tissue engineering, and biosensing are discussed.

A Metal-free Battery with Pure Ionic Liquid Electrolyte

Metal or metal-ion-based batteries represent the mainstream battery technology, in which metal ions either participate in the electrode redox reaction or act as the charge carrier in the electrolyte. The principle guides battery designs and leads to the most widely adopted battery construction of metal-ion acceptor/metal salt in solvent/metal-ion donor. Although these architectures have seen significant progress, there are still many issues with them, including dendrite growth, solid-electrolyte interface corruption, and safety concerns. In this article, the intercalation/deintercalation of organic cations other than metal ions is explored in an all-organic battery composed of organic anode/cathode and pure ionic liquid electrolyte. This metal-free and solvent-free concept has been demonstrated by polyimide/1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide/polytriphenylamine full-cell, through which capacity near theoretical value, more than 5,000 cycling life, rate capability up to 200 C, and remarkable low-temperature performance has been achieved. Our work provides an alternate way of developing future efficient, safe, green, and versatile batteries.

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Metal-free battery was demonstrated by PI5/EMITFSI/PTPAn cell

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Organic cation/anion storage was realized

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Ionic liquid was used alone as electrolyte and acted as the cation/anion supplier

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PI5/EMITFSI/PTPAn cell exhibited superstable cycling and remarkable rate capability

Organic Carbonyl Compounds for Sodium-Ion Batteries: Recent Progress and Future Perspectives

Sodium-organic batteries, which use organic materials as the electrodes in sodium-ion batteries, are an attractive alternative to conventional lithium-ion batteries for next-generation sustainable and versatile energy storage devices owing to the abundant sodium resources and environmental friendly features. However, organics used in sodium-ion batteries also encounter some issues such as low redox potential, high solubility in the electrolyte, and low conductivity. In response, altering the aromatic system/attaching electron-withdrawing groups, constructing polymers, and incorporating a conductive matrix are effective strategies. This review summarizes and briefly discusses recent organic carbonyl compounds for sodium-organic batteries from the viewpoint of function-oriented design, including function evolution from small-molecule compounds to polymers, then composites, and finally flexible electrodes. In particular, as a timely overview, carbonyl-based organic flexible electrodes for sodium-organic batteries are also highlighted for the first time.

Three-dimensional graphene-based polymer nanocomposites: preparation, properties and applications

Motivated by the unique structure and outstanding properties of graphene, three-dimensional (3D) graphene-based polymer nanocomposites (3D-GPNCs) are considered as new generation materials for various multi-functional applications. This review presents an overview of the preparation, properties and applications of 3D-GPNCs. Three main approaches for fabricating 3D-GPNCs, namely 3D graphene based template, polymer particle/foam template, and organic molecule cross-linked graphene, are introduced. A thorough investigation and comparison of the mechanical, electrical and thermal properties of 3D-GPNCs are performed and discussed to understand their structure-property relationship. Various potential applications of 3D-GPNCs, including energy storage and conversion, electromagnetic interference shielding, oil/water separation, and sensors, are reviewed. Finally, the current challenges and outlook of these emerging 3D-GPNC materials are also discussed.

Aromatic Polyimide/Graphene Composite Organic Cathodes for Fast and Sustainable Lithium-Ion Batteries

A composite organic cathode material based on aromatic polyimide (PI) and highly conductive graphene was prepared through a facile in situ polymerization method for application in lithium-ion batteries. The in situ polymerization generated intimate contact between PI and electronically conductive graphene, resulting in conductive composites with highly reversible redox reactions and good structure stability. The synergistic effect between PI and graphene enabled not only a high reversible capacity of 232.6 mAh g^-1 at a charge-discharge rate of C/10 but also exceptionally high-rate cycling stability, that is, a high capacity of 108.9 mAh g^-1 at a very high charge-discharge rate of 50C with a capacity retention of 80 % after 1000 cycles. This improved electrochemical performance resulted from the combination of stable redox reversibility of PI and high electronic conductivity of the graphene additive. The graphene-based composite also exhibited much better performance than composites based on multi-walled carbon nanotubes and the conductive carbon black C45 in terms of specific capacity and long-term cycling stability under the same charge-discharge rates.

Self-Assembled Graphene-Based Architectures and Their Applications

Due to unique planar structures and remarkable thermal, electronic, and mechanical properties, chemically modified graphenes (CMGs) such as graphene oxides, reduced graphene oxides, and the related derivatives are recognized as the attractive building blocks for "bottom-up" nanotechnology, while self-assembly of CMGs has emerged as one of the most promising approaches to construct advanced functional materials/systems based on graphene. By virtue of a variety of noncovalent forces like hydrogen bonding, van der Waals interaction, metal-to-ligand bonds, electrostatic attraction, hydrophobic-hydrophilic interactions, and π-π interactions, the CMGs bearing various functional groups are highly desirable for the assemblies with themselves and a variety of organic and/or inorganic species which can yield various hierarchical nanostructures and macroscopic composites endowed with unique structures, properties, and functions for widespread technological applications such as electronics, optoelectronics, electrocatalysis/photocatalysis, environment, and energy storage and conversion. In this review, significant recent advances concerning the self-assembly of CMGs are summarized, and the broad applications of self-assembled graphene-based materials as well as some future opportunities and challenges in this vibrant area are elucidated.