Potassium ion batteries (PIBs) are recognized as one promising candidate for future energy storage devices due to their merits of cost‐effectiveness, high‐voltage, and high‐power operation. Many ...efforts have been devoted to the development of electrode materials and the progress has been well summarized in recent review papers. However, in addition to electrode materials, electrolytes also play a key role in determining the cell performance. Here, the research progress of electrolytes in PIBs is summarized, including organic liquid electrolytes, ionic liquid electrolytes, solid‐state electrolytes and aqueous electrolytes, and the engineering of the electrode/electrolyte interfaces is also thoroughly discussed. This Progress Report provides a comprehensive guidance on the design of electrolyte systems for development of high performance PIBs.
Electrolytes play a critical role in the electrochemical performance of emerging potassium‐ion batteries (PIBs). The research progress on electrolytes of PIBs is summarized in terms of fundamental properties, optimization of electrolyte components and engineering of electrode/electrolyte interfaces, providing a comprehensive guidance on designing more suitable electrolytes for high‐performance PIBs.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
p‐Benzoquinone (BQ) is a promising cathode material for lithium‐ion batteries (LIBs) due to its high theoretical specific capacity and voltage. However, it suffers from a serious dissolution problem ...in organic electrolytes, leading to poor electrochemical performance. Herein, two BQ‐derived molecules with a near‐plane structure and relative large skeleton: 1,4‐bis(p‐benzoquinonyl)benzene (BBQB) and 1,3,5‐tris(p‐benzoquinonyl)benzene (TBQB) are designed and synthesized. They show greatly decreased solubility as a result of strong intermolecular interactions. As cathode materials for LIBs, they exhibit high carbonyl utilizations of 100% with high initial capacities of 367 and 397 mAh g−1, respectively. Especially, BBQB with better planarity presents remarkably improved cyclability, retaining a high capacity of 306 mAh g−1 after 100 cycles. The cycling stability of BBQB surpasses all reported BQ‐derived small molecules and most polymers. This work provides a new molecular structure design strategy to suppress the dissolution of organic electrode materials for achieving high performance rechargeable batteries.
An effective molecular design strategy is developed to suppress the dissolution of benzoquinone‐derived organic electrode materials. Two novel benzoquinone‐derived molecules with near‐plane structure and relatively large skeleton are synthesized to increase the π–π stacking, which show greatly decreased solubility and enhanced electrochemical performance.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Organic cathode materials as economical and environment‐friendly alternatives to inorganic cathode materials have attracted comprehensive attention in potassium‐ion batteries (KIBs). Nonetheless, ...active material dissolution and mismatched electrolytes result in insufficient cycle life that definitely hinders their practical applications. Here, a significantly improved cycle life of 1000 cycles (80% capacity retention) on a practically insoluble organic cathode material, anthraquinone‐1,5‐disulfonic acid sodium salt, is realized, in KIBs through a solid‐electrolyte interphase (SEI) regulation strategy by ether‐based electrolytes. Such an excellent performance is attributed to the robust SEI film and fast reaction kinetics. More importantly, the ether‐electrolyte‐derived SEI film has a protective inorganic‐rich inner layer arising from the prior decomposition of potassium salts to solvents, as revealed by X‐ray photoelectron spectroscopy analysis and computational studies on molecular orbital energy levels. The findings shed light on the critical roles of electrolytes and the corresponding SEI films in enhancing performance of organic cathodes in KIBs.
Solid‐electrolyte interphase (SEI) regulation by electrolytes is an effective approach to boost K‐storage performance of organic cathodes in potassium‐ion batteries. The prior decomposition of potassium salts to the ether solvent molecules creates a compact and sustainable inorganic‐rich inner layer of SEI, rendering fast reaction kinetics and a long cycle life of 1000 cycles with 80% capacity retention.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Organic cathode materials have attracted extensive attention because of their diverse structures, facile synthesis, and environmental friendliness. However, they often suffer from insufficient ...cycling stability caused by the dissolution problem, poor rate performance, and low voltages. An in situ electropolymerization method was developed to stabilize and enhance organic cathodes for lithium batteries. 4,4′,4′′‐Tris(carbazol‐9‐yl)‐triphenylamine (TCTA) was employed because carbazole groups can be polymerized under an electric field and they may serve as high‐voltage redox‐active centers. The electropolymerized TCTA electrodes demonstrated excellent electrochemical performance with a high discharge voltage of 3.95 V, ultrafast rate capability of 20 A g−1, and a long cycle life of 5000 cycles. Our findings provide a new strategy to address the dissolution issue and they explore the molecular design of organic electrode materials for use in rechargeable batteries.
An in situ electropolymerization method was developed to enhance the performance of organic cathodes. 4,4′,4′′‐Tris(carbazol‐9‐yl)‐triphenylamine (TCTA) was employed because carbazole groups can be polymerized under an electric field and they may serve as high‐voltage redox‐active centers. Ultrafast rate performance (20 A g−1), long cycle life (5000 cycles), and high voltage (3.95 V) were demonstrated.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Organic electrode materials have attracted great interest for next‐generation lithium‐ion batteries owing to their merits of low cost, resource sustainability, and environmental friendliness. ...Dissolution in organic electrolyte is one of critical factors that limit their development, and constructing corresponding polymers is an effective way to prevent it. Herein, the synthesis of benzoquinone‐ and naphthoquinone‐bearing polymers by ring‐opening metathesis polymerization of monomers with an exo‐type four‐membered ring between polymerizable norbornene and redox‐active quinone units is reported. They exhibit significantly reduced solubility and clearly enhanced electrochemical performance. In particular, a high capacity (189.7 mAh g−1 at 0.1 C, 1 C=216.1 mA g−1), stable cycling (75.6 % capacity retention after 500 cycles at 2 C), and good rate capability (retaining 80.4 % from 0.1 to 2 C) were obtained for the naphthoquinone‐bearing polymer, which stand out among naphthoquinone‐bearing polymer electrode materials. This work offers rational molecular design and a new polymerization strategy to construct high‐performance polymer electrode materials.
ROMPing to electrodes: Benzoquinone‐ and naphthoquinone‐bearing polymers are synthesized by ring‐opening metathesis polymerization (ROMP). As electrodes in lithium‐ion batteries, their reduced solubilities in organic electrolytes compared with their monomers result in significantly enhanced cycling stability and high voltages. These results highlight a new polymerization strategy to construct high‐performance organic electrode materials.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this work, a 9,10-anthraquinone (AQ) derivative functionalized by two methoxy groups, 2,6-dimethoxy-9,10-anthraquinone (DMAQ), was synthesized and its electrochemical performance was ...comprehensively studied with different electrolyte concentrations. Density functional theory (DFT) calculations demonstrate that there exists a conjugation effect between oxygen atoms of methoxy groups and the AQ skeleton, which could extend the conjugate plane and increase intermolecular interaction. As a result, DMAQ shows considerably reduced solubility in ether solvent/electrolyte and greatly enhanced cycling performance compared with those of AQ. Interestingly, it is found that the electrolyte concentration plays an important role in determining the electrochemical performance. Cycling under a relatively low (2 M) or high (6 M) concentration electrolyte of lithium bis(trifluoromethanesulfonyl)imide in a mixture solvent of 1,3-dioxolane and 1,2-dimethoxyethane (1/1, v/v) displays unsatisfied cell performance. While a moderate electrolyte concentration of 4 M delivers the highest initial capacity and the best cycling stability. The work would shed light on the rational molecular structure design and electrolyte concentration optimization for achieving the high electrochemical performance of organic electrode materials.
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IJS, KILJ, NUK, PNG, UL, UM
Organic electrode materials for lithium‐ion batteries have attracted significant attention in recent years. Polymer electrode materials, as compared to small‐molecule electrode materials, have the ...advantage of poor solubility, which is beneficial for achieving high cycling stability. However, the severe entanglement of polymer chains often leads to difficulties in preparing nanostructured polymer electrodes, which is vital for achieving fast reaction kinetics and high utilization of active sites. This study demonstrates that these problems can be solved by the in situ electropolymerization of electrochemically active monomers in nanopores of ordered mesoporous carbon (CMK‐3), combining the advantages of the nano‐dispersion and nano‐confinement effects of CMK‐3 and the insolubility of the polymer materials. The as‐prepared nanostructured poly(1‐naphthylamine)/CMK‐3 cathode exhibits a high active site utilization of 93.7%, ultrafast rate capability of 60 A g−1 (≈320 C), and an ultralong cycle life of 10000 cycles at room temperature and 45000 cycles at −15 °C. The study herein provides a facile and effective method that can simultaneously solve both the dissolution problem of small‐molecule electrode materials and the inhomogeneous dispersion issue of polymer electrode materials.
A brand‐new strategy of in situ electropolymerization in nanopores of CMK‐3 is developed to fabricate nanostructured polymer cathode for lithium‐organic batteries, which enables high capacity (close to its theoretical value), ultrafast (60 A g−1) and ultralong cycle life at both room temperature (10000 cycles) and low temperature of −15 °C (45000 cycles).
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
To address the dissolution issue and enhance the electrochemical performance of organic electrode materials, herein, a bipolar organic cathode was prepared by
in-situ
electropolymerization of ...amino-phenyl carbazole naphthalene diimide (APCNDI). APCNDI is composed of n-type 1,4,5,8-naphthalene tetracarboxylic diimide that stores Li cations and p-type carbazole groups which react with anions and serve as polymerization sites. Electropolymerization completely eliminated the dissolution problem of APCNDI, and the electropolymerized cathode demonstrated a bipolar reaction with excellent electrochemical performance, stable cycling performance with a capacity retention of 92 mA h g
−1
after 1000 cycles, and a superior rate performance of 72 mA h g
−1
at 10 A g
−1
. The bipolar feature and reactions of APCNDI were systematically investigated and verified by multiple characterization techniques. Our findings provide a novel strategy for the design and fabrication of electrodes for high-performance organic batteries.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In recent years, rainstorm chain disasters occurred frequently in megacities in China, seriously threatening people’s life and property safety and social stability. Therefore, it is essential to take ...effective measures to timely break the chain and mitigate the disasters.This study thoroughly analyzes the disaster chain system of rainstorms and studies the trend deduction model of waterlogging disasters and the important role of various deductive simulation results in intercepting the disaster chain. It also proposes a chain breaking idea of combining simulation deduction with comprehensive response and clarifies the response strategies of various emergency bodies in the disaster response in megacities. Moreover, an overall response idea based on the policy of preparation, supervision, simulation, connection, and rescue is proposed. In view of the key problems including multi-department plan coordination, multi-dimensional information aggregation, multi-level accurate warning, and multi-team linked dispatching, we propose the following countermeasures: completing the comprehensive plan system, constructing a monitoring and early warning network, improving simulation and deduction application, strengthening joint response ability, and boosting the accurate rescue ability. Furthermore, development suggestions are proposed from the following aspects: formulation of policies and regulations, compilation of standards, application of intelligent technology, promotion of intelligent early warning and directional release technology, and formation of a new pattern of “national emergency.”
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