Severe Ni dissolution and the resulting impedance rise for the single-crystal LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode is the main challenge greatly hindering its industrial applications. Herein, we propose a novel concept of anchoring interfacial nickel cations on a single-crystal LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode through controllable electron transfer. This strategy is realized by applying an ultrathin PMMA surface layer. Different from traditional physical coatings, electron transfer from Ni 2+ to the ester group is confirmed, which contributes to anchoring the interfacial Ni cations and effectively inhibits Ni dissolution into the organic electrolyte. Meanwhile, Li diffusion on the cathode surface is significantly improved. As a result, the electrochemical performance of the LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode with a PMMA layer is improved. A reversible capacity of 181.1 mAh g −1 at 1C rate is obtained with enhanced rate capability and cycling stability. Moreover, the modified LiNi 0.8 Co 0.1 Mn 0.1 O 2 is able to work well at high voltage and high temperature, especially with incorporation of polyvinylidene fluoride.

Interfacial modification is one of the most important technologies to improve the overall electrochemical properties for Ni-rich cathode. Herein, a novel strategy of in-situ planting electrolyte film-forming additive on single...

Single-crystalline cathodes are the most promising candidates for highenergy-density lithium-ion batteries (LIBs). Compared to their polycrystalline counterparts, single-crystalline cathodes have advantages over liquid-electrolyte-based LIBs in terms of cycle life, structural stability, thermal stability, safety, and storage but also have a potential application in solid-state LIBs. In this review, the development history and recent progress of single-crystalline cathodes are reviewed, focusing on properties, synthesis, challenges, solutions, and characterization. Synthesis of single-crystalline cathodes usually involves preparing precursors and subsequent calcination, which are summarized in the details. In the following sections, the development issues of single-crystalline cathodes, including kinetic limitations, interfacial side reactions, safety issues, reversible planar gliding and micro-cracking, and particle size distribution and agglomeration, are systematically analyzed, followed by current solutions and characterization techniques. Finally, this review is concluded with proposed research thrusts for the future development of singlecrystalline cathodes.

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Li-rich Mn-based layered oxide cathodes with a high discharge capacity hold great promise for high energy density lithium-ion batteries. However, application is hampered by voltage and capacity decay and gas evolution during cycling due to interfacial side reactions. Here, we report coating by oxygen-deficient perovskite La 0.9 Sr 0.1 CoO 3 using the Pechini process. X-ray photoelectron spectroscopy and scanning transmission electron microscopy both exhibit a uniform coating layer with a high oxygen vacancy concentration. The coating effectively mitigates the first cycle irreversible capacity loss and voltage decay while increasing cyclability. Optimized coating improves capacity retention from 55.6% to 84.8% after 400 cycles at 2 C. Operando differential electrochemical mass spectroscopy shows that such a coating can significantly mitigate the release of oxygen and carbon dioxide. Electrochemical impedance spectroscopy and post-mortem analysis indicate that the coating layer forms a stable interface and restricts structure evolution and cation mixing during cycling, conferring these cathode materials with better cycling and voltage stability. The perovskite can be applied to other cathodes with high voltage and capacity to suppress interfacial side reactions toward developing stable high energy density batteries.

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3-Substituted phthalides are widely distributed in plants and fungi. They are active ingredients in traditional Chinese herbal medicines, and have attracted much attention in modern medicinal chemistry. The synthetic methods of 3-substituted phthalides are reviewed, especially those in enantioselective manners. The main approach involves: (a) construction of lactones from C-C bond formation reactions, e.g. an aldol/lactonization cascade reaction of 2-acylbenzoates and alikes, (b) construction of lactones via C-O bond formation reactions, e.g. reductive lactonization of 2-acylbenzoates or reduction of 3-alkenyl phthalides, intramolecular oxidation/lactonization, or intramolecular redox/lactonization. These methods are of great significance for the high stereoselective synthesis of phthalides and drug research. Keywords phthalide; isobenzofuran-1(3H)-one; synthesis; enantioselectivity; natural product 天然产物在药物研发中发挥了关键作用, 许多现代 药物的开发受到了各种天然产物的启发 [1][2] . 苯酞, 即异 苯并呋喃-1(3H)-酮, 为具有 γ-内酯与苯稠合的双环结构 物质(图 1, 1). 某些植物(如川芎和当归)以及真菌中就含 有这类化合物 [3] . 目前, 已分离鉴定出近两百种含苯酞 骨架的天然化合物, 这些化合物在取代基的性质、位置 以及苯环的氧化程度方面表现出差异. 根据苯酞单元的 结构特征, 通常分为三类 [4][5] : (a) 3-未取代的苯酞, (b) 3-取代的苯酞和(c)苯酞二聚物. 这些物质显示出重要的 临床特性, 例如抗血小板聚集、抗血栓形成、防止脑缺 血、抗心绞痛、调节心脏功能及中枢神经系统的作 用 [4,[6][7][8] . 这类分子的生物活性归因于苯酞中的环内酯结 构 [9] . 尽管苯酞类化合物的结构和生物多样性引起了人 们广泛的兴趣, 但是大规模从天然产物中获取这类化合 物并不现实, 因此采用化学方法合成这些化合物具有重 要意义. 本综述将简述苯酞类化合物的结构多样性、生 物活性, 总结在生物活性方面更为重要的 3-取代苯酞的 代表性合成方法, 为相关研究提供参考. 生物活性具有苯酞结构骨架的霉酚酸(图 1, 2)是一种免疫抑 制剂, 用于器官移植(如肾脏移植)的术后恢复 [10][11] ; 化 合物 3 能抑制前列腺素 E 2 的生成 [12] ; 4 具有抗癌和抗抑 郁活性 [13] .大多数天然苯酞类化合物属于 3-取代的苯酞(图 1, 5～11), 这些化合物往往具有丰富的药理活性. 具有芹 菜特有气味的丁苯酞 5 (NBP, 图 1), 能够抑制血小板凝 集、改善微循环、减轻缺血性脑损伤, 是治疗缺血性脑 卒中的药物 [14] , (S)-NBP 在某些情况下效果更佳 [15] ; 化