Nanoengineered Organic Electrodes for Highly Durable and Ultrafast Cycling of Organic Sodium-Ion Batteries

Organic Supercapacitors as the Next Generation Energy Storage Device: Emergence, Opportunity, and Challenges

Harnessing new materials for developing high-energy storage devices set off research in the field of organic supercapacitors. Various attractive properties like high energy density, lower device weight, excellent cycling stability, and impressive pseudocapacitive nature make organic supercapacitors suitable candidates for high-end storage device applications. This review highlights the overall progress and future of organic supercapacitors. Sustainable energy production and storage depend on low cost, large supercapacitor packs with high energy density. Organic supercapacitors with high pseudocapacitance, lightweight form factor, and higher device potential are alternatives to other energy storage devices. There are many recent ongoing research works that focus on organic electrolytes along with the material aspect of organic supercapacitors. This review summarizes the current research status and the chemistry behind the storage mechanism in organic supercapacitors to overcome the challenges and achieve superior performance for future opportunities.

Molecular and Morphological Engineering of Organic Electrode Materials for Electrochemical Energy Storage

Organic electrode materials (OEMs) can deliver remarkable battery performance for metal-ion batteries (MIBs) due to their unique molecular versatility, high flexibility, versatile structures, sustainable organic resources, and low environmental costs. Therefore, OEMs are promising, green alternatives to the traditional inorganic electrode materials used in state-of-the-art lithium-ion batteries. Before OEMs can be widely applied, some inherent issues, such as their low intrinsic electronic conductivity, significant solubility in electrolytes, and large volume change, must be addressed. In this review, the potential roles, energy storage mechanisms, existing challenges, and possible solutions to address these challenges by using molecular and morphological engineering are thoroughly summarized and discussed. Molecular engineering, such as grafting electron-withdrawing or electron-donating functional groups, increasing various redox-active sites, extending conductive networks, and increasing the degree of polymerization, can enhance the electrochemical performance, including its specific capacity (such as the voltage output and the charge transfer number), rate capability, and cycling stability. Morphological engineering facilitates the preparation of different dimensional OEMs (including 0D, 1D, 2D, and 3D OEMs) via bottom-up and top-down methods to enhance their electron/ion diffusion kinetics and stabilize their electrode structure. In summary, molecular and morphological engineering can offer practical paths for developing advanced OEMs that can be applied in next-generation rechargeable MIBs.

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Minimal TiO2 Coupled with Conductive Polymer-Stimulated Synergistic Effect on Fast and Reversible Sodium-Ion Storage for Bismuth Sulfide

Designing multiphase composition is believed to availably boost the structural integrity and electrochemical properties of sodium-ion battery anodes. Herein, a conceive of nanoflowers, assembled with Bi₂S₃ nanorods, is demonstrated to construct the multiphase composition involving TiO₂ coating and polypyrrole (PPy) encapsulation. Bi₂S₃ acted as the dominating active material, in consideration of the low content of TiO₂, which ensured the high capacity of the composite. The dual-structural restrain of the TiO₂ and PPy coatings can effectively alleviate volume variation based on the pseudo-"zero-strain" effect of TiO₂ and high flexibility of PPy shells. Meanwhile, the heterointerface greatly enhanced the coupling effect between Bi₂S₃ and TiO₂ and thus improved the electrochemical performance, which was proved by the results of density functional theory calculation and electrochemical tests. Combining the regulation from the Bi₂S₃/TiO₂ heterojunction and the dual-structural restrain effect, the Bi₂S₃/TiO₂@PPy electrode exhibited excellent rate performance and superior cycle stability (275.8 mA h g^-1 over 500 cycles at 10 A g^-1). This study indicates that designing multiphase composition can be very promising and provides a structural insight to construct high stability in electrodes for sodium-ion batteries.

Recent Advances and Perspectives on the Polymer Electrolytes for Sodium/Potassium-Ion Batteries

Owing to the low cost of sodium/potassium resources and similar electrochemical properties of Na⁺ /K⁺ to Li⁺ , sodium-ion batteries (SIBs) and potassium-ion batteries (KIBs) are regarded as promising alternatives to lithium-ion batteries (LIBs) in large-scale energy storage field. However, traditional organic liquid electrolytes bestow SIBs/KIBs with serious safety concerns. In contrast, quasi-/solid-phase electrolytes including polymer electrolytes (PEs) and inorganic solid electrolytes (ISEs) show great superiority of high safety. However, the poor processibility and relatively low ionic conductivity of Na⁺ and K⁺ ions limit the further practical applications of ISEs. PEs combine some merits of both liquid-phase electrolytes and ISEs, and present great potentials in next-generation energy storage systems. Considerable efforts have been devoted to improving their overall properties. Nevertheless, there is still a lack of an in-depth and comprehensive review to get insights into mechanisms and corresponding design strategies of PEs. Herein, the advantages of different electrolytes, particularly PEs are first minutely reviewed, and the mechanism of PEs for Na⁺ /K⁺ ion transfer is summarized. Then, representative researches and recent progresses of SIBs/KIBs based on PEs are presented. Finally, some suggestions and perspectives are put forward to provide some possible directions for the follow-up researches.