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.

storage and conversion. [8a,c,11] For example, Xu et al. summarized the advances of MOFs and their derivatives for electrochemical applications, including supercapacitors, batteries, and fuel cells. [11a] Besides, Zou et al. presented some engineering strategies to improve the performance of MOF-related materials for energy storage and conversion. [11i] However, few review articles focus on MOF-related materials as cathode materials for alkali metal ion batteries (LIBs, SIBs, and PIBs). Besides, the relationship between fundamental characteristics and electrochemical performance for MOF-related cathode materials is less discussed. Given the key role of the cathode materials in the batteries, in this review, we present design principles for promoting the electrochemical performance of MOF-related materials in terms of component/structure design, composite fabrication, and morphology engineering. Last, the challenges and perspectives about MOF-related cathode materials for alkali metal ion batteries are discussed.

Polymer electrode materials are often poorly soluble in liquid organic electrolytes of lithium-ion batteries, yet they suffer from issues of severe agglomeration and complicated synthesis processes, which hinder their practical applications. Herein, spherical cross-linked quinone-amine polymer nanoparticles (denoted as PQANPs) are synthesized through a facile precipitation polymerization, which can effectively address the agglomeration problems of polymer electrode materials. The cross-linking degrees of polymers and diameters of PQANPs can be facilely tuned by adjusting the feed ratios of p-benzoquinone to 3,3′-diaminobenzidine. The optimized PQANP demonstrates excellent electrochemical performance with an ultrafast rate capability of 25 A g −1 and an ultralong cycle life of 20 000 cycles, which exceed all benzoquinone-based polymer electrode materials reported in the literature. The findings offer an efficient and convenient strategy for high-performance nanostructured polymer electrode materials.

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.

In‐situ electro‐polymerization of redox‐active monomers has been proved to be a novel and facile strategy to prepare polymer electrodes with superior electrochemical performance. The monomer molecular structure would have a profound impact on electro‐polymerization behavior and thus electrochemical performance. However, this impact is poorly understood and has barely been investigated yet. Herein, three carbazole‐based monomers, 9‐phenylcarbazole (CB), 1,4‐bis(carbazol‐9‐yl)benzene (DCB), and 2,6‐bis(carbazol‐9‐yl)naphthalene (DCN), were applied to study the above issue systematically and achieve excellent long cycle performance. The monomers were rationally designed with different polymerizable sites and solubilities. It was found that a monomer with increased polymerizable sites and decreased solubility brought about enhanced electrochemical performance. This is because poor solubility could enhance utilization of the monomer for polymerization and more polymerizable sites could lead to a stable crosslinked polymer network after electro‐polymerization. DCN with four polymerizable sites and the poorest solubility displayed the best electrochemical performance, which showed stable cycling up to 5000 cycles with high capacity retention of 76.2 % (among the best cycle in the literature). Our work for the first time reveals the relationship between monomer structure and in‐situ electro‐polymerization behavior. This work could shed light on the structure design/optimization of monomers for high‐performance polymer electrodes prepared through in‐situ electro‐polymerization.