水系锌离子电池用钒基正极材料的研究进展

水系锌离子电池(aqueous zinc-ion batteries,AZIBs)具有高安全性、低生产成本、锌资源丰富和环境友好等优点,被认为是未来大规模储能系统中极具发展前景的储能装置。目前,AZIBs的研究关键之一在于开发具有稳定结构和高容量的锌离子可脱嵌正极材料。钒基化合物用作AZIBs正极时,表现出可逆容量高和结构丰富可变等特点,受到了广泛的关注和研究。然而,钒基化合物的储锌机理较复杂,不同材料通常表现出各异的电化学性能和储能机理。在本综述中,我们全面地阐述了钒基化合物的储能机制,并探讨了钒基材料在水系锌离子电池中的应用和发展近况,以及它们的性能优化策略。在此基础上,也进一步地展望了水系锌离子电池及其钒基正极材料的发展方向。     

Recent advancements in LiCoPO4 cathodes using electrolyte additives

Olivine-type LiCoPO₄ proves its intriguing electrochemical properties as a highly valuable voltage cathode material for the next-generation lithium-ion batteries (LIB) with the benefits of a high operating potential of ～4.8 V versus Li and a high theoretical capacity of ～167 mAh g^?1. However, several limitations in attaining high coulombic efficiency, good rate capability, and long cycle stability need to be improved before implementing into commercial applications. Thus, various strategies involve advancing the LiCoPO₄ performances via synthesis routes, surface modification, doping with iso- and alio-valent substitutions, etc., to achieve competitive performance with other commercial cathodes. Apart from these strategies, suitable electrolytes and additives are equally important to alleviate the electrolyte oxidation at high voltages to develop next-generation LIBs. In this work, we summarize the structural and physical properties of LiCoPO₄ with information about the strategies to enhance the performance of LiCoPO₄ in the beginning and discuss the method of electrolyte optimization using various additives in detail. Future perspectives dictate the important insights into practical issues that can accelerate the progress of LiCoPO₄-based LIBs in energy storage applications toward practical use.     

Methods for enhancing the capacity of electrode materials in low-temperature lithium-ion batteries

Lithium-ion batteries(LIBs) have evolved into the mainstream power source of ene rgy sto rage equipment by reason of their advantages such as high energy density,high power,long cycle life and less pollution.With the expansion of their applications in deep-sea exploration,aerospace and military equipment,special working conditions have placed higher demands on the low-temperature performance of LIBs.However,at low temperatures,the severe polarization and inferior electrochemical activity of electrode materials cause the acute capacity fading upon cycling,which greatly hindered the further development of LIBs.In this review,we summarize the recent important progress of LIBs in low-temperature operations and introduce the key methods and the related action mechanisms for enhancing the capacity of the various cathode and anode materials.It aims to promote the development of high-performance electrode materials and broaden the application range of LIBs.     

锂离子电池高电压正极粘结剂的研究进展

锂离子电池在高电压下会导致严重的电解液分解以及不稳定的正极与电解质界面问题,严重制约高电压正极材料的商业化.粘结剂不仅可以将正极活性材料和导电炭紧密粘结在集流体上,还对构建电解质与正极之间的多尺度相容性界面起积极作用,因此,粘结剂的优化可以有效解决上述难题.本文提出了高电压锂离子电池正极粘结剂需具备的必要条件,如:粘结性能和机械性能优异,具有出色的电化学稳定性和热力学稳定性以及良好的离子和电子传输能力等.综述了近些年来高电压正极粘结剂的研究及发展现状,通过天然粘结剂和合成粘结剂对目前已报道的高电压粘结剂进行了评述,介绍了各种粘结剂对电极的粘结性能和包覆以及对锂离子电池性能的影响机制,重点阐述了粘结剂分子结构中的极性基团与活性物质间的相互作用,如氢键和离子-偶极相互作用,并讨论了设计开发高电压正极粘结剂的途径以及展望了高电压正极粘结剂的发展前景.     

Improving the stability of LiNi_(0.80)Co_(0.15)Al_(0.05)O_2 by AlPO_4 nanocoating for lithium-ion batteries

Nickel-rich layered materials,such as LiNi_(0.8)0Co_(0.15)Al_(0.05)O_2(NCA),have been considered as one alternative cathode materials for lithium-ion batteries(LIBs) due to their high capacity and low cost.However,their poor cycle life and low thermal stability,caused by the electrode/electrolyte side reaction,prohibit their prosperity in practical application.Herein,AlPO4 has been homogeneously coated on the surface of NCA via wet chemical method towards the target of protecting NCA from the attack of electrolyte.Compared with the bare NCA,NCA@AlPO_4 electrode delivers high capacity without sacrificing the discharge capacity and excellent cycling stability.After 150 cycles at 0.5 C between 3.0-4.3 V,the capacity retention of the coated material is 86.9%,much higher than that of bare NCA(66.8%).Furthermore,the thermal stability of cathode is much improved due to the protection of the uniform coating layer on the surface of NCA.These results suggest that AlPO4 coated NCA materials could act as one promising candidate for next-generation LIBs with high energy density in the near future.     

One-Step Calcination Synthesis of Bulk-Doped Surface-Modified Ni-Rich Cathodes with Superlattice for Long-Cycling Li-Ion Batteries

Nickel-rich (Ni≥90 %) layered cathodes are critical materials for achieving higher-energy-density and lower-cost next-generation Li-ion batteries (LIBs). However, their bulk and interface structural instabilities significantly impair their electrochemical performance, thus hindering their widespread adoption in commercial LIBs. Exploiting Ti and Mo diffusion chemistry, we report one-step calcination to synthesize bulk-to-surface modified LiNi_0.9Co_0.09Mo_0.01O₂ (NCMo90) featuring a 5 nm Li₂TiO₃ coating on the surface, a Mo-rich Li⁺/Ni²⁺ superlattice at the sub-surface, and Ti-doping in the bulk. Such a multi-functional structure effectively maintains its structural integrity upon cycling. As a result, such NCMo90 exhibits a high initial capacity of 221 mAh g⁻¹ at 0.1 C, excellent rate performance (184 mAh g⁻¹ at 5 C), and high capacity retention of 94.0 % after 500 cycles. This work opens a new avenue to developing industry-applicable Ni-rich cathodes for next-generation LIBs.     

表面限域掺杂提升高比能正极材料稳定性

Lithium ion batteries (LIBs) have broad applications in a wide variety of a fields pertaining to energy storage devices. In line with the increasing demand in emerging areas such as long-range electric vehicles and smart grids, there is a continuous effort to achieve high energy by maximizing the reversible capacity of electrode materials, particularly cathode materials. However, in recent years, with the continuous enhancement of battery energy density, safety issues have increasingly attracted the attention of researchers, becoming a non-negligible factor in determining whether the electric vehicle industry has a foothold. The key issue in the development of battery systems with high specific energies is the intrinsic instability of the cathode, with the accompanying question of safety. The failure mechanism and stability of high-specific-capacity cathode materials for the next generation of LIBs, including nickel-rich cathodes, high-voltage spinel cathodes, and lithium-rich layered cathodes, have attracted extensive research attention. Systematic studies related to the intrinsic physical and chemical properties of different cathodes are crucial to elucidate the instability mechanisms of positive active materials. Factors that these studies must address include the stability under extended electrochemical cycles with respect to dissolution of metal ions in LiPF₆-based electrolytes due to HF corrosion of the electrode; cation mixing due to the similarity in radius between Li⁺ and Ni²⁺; oxygen evolution when the cathode is charged to a high voltage; the origin of cracks generated during repeated charge/discharge processes arising from the anisotropy of the cell parameters; and electrolyte decomposition when traces of water are present. Regulating the surface nanostructure and bulk crystal lattice of electrode materials is an effective way to meet the demand for cathode materials with high energy density and outstanding stability. Surface modification treatment of positive active materials can slow side reactions and the loss of active material, thereby extending the life of the cathode material and improving the safety of the battery. This review is targeted at the failure mechanisms related to the electrochemical cycle, and a synthetic strategy to ameliorate the properties of cathode surface locations, with the electrochemical performance optimized by accurate surface control. From the perspective of the main stability and safety issues of high-energy cathode materials during the electrochemical cycle, a detailed discussion is presented on the current understanding of the mechanism of performance failure. It is crucial to seek out favorable strategies in response to the failures. Considering the surface structure of the cathode in relation to the stability issue, a newly developed protocol, known as surface-localized doping, which can exist in different states to modify the surface properties of high-energy cathodes, is discussed as a means of ensuring significantly improved stability and safety. Finally, we envision the future challenges and possible research directions related to the stability control of next-generation high-energy cathode materials.     

富锂正极材料结构设计和表面调控的研究进展

富锂正极材料因具有较高的理论能量密度,被视为极具发展潜能的新一代正极材料,但该材料在循环过程中容量和电压衰减显著,导致其实际商业应用受阻.本文综合评述了通过结构设计和表面调控提高富锂正极材料储锂性能的研究进展,介绍了富锂正极材料的充放电工作机制,及导致其比容量和电压衰减的原因,讨论了近年来通过新型结构设计(如构筑蛋黄-蛋壳中空结构、中空多壳层结构等)和表面调控(如尺寸控制、暴露晶面控制、表面尖晶石化、表面包覆、表面掺杂等）策略,抑制富锂正极材料表面氧析出和晶型转变并稳定材料结构,从而抑制电压和比容量衰减,有效提高电池的循环寿命和库伦效率的相关研究成果,最后,提出了通过结构设计和表面调控提高富锂正极材料电化学性能面临的挑战,并对未来发展方向进行了展望.     

锂离子电池正极材料中的极化子现象理论计算研究进展

In addition to their extensive commercial application in electronic devices such as cell phones and laptops, lithium-ion batteries (LIBs) are most suitable to fulfill the energy storage requirements of electric vehicles because of their recognized safety, portability, and high energy density. Cathodes are the most important part of LIBs, and various cathode materials have been widely investigated over the past decades. Polaron formation has been attracting increasing attention in the research of cathode materials, as it limits electron conduction. In particular, polarons are responsible for low electronic conductivity in cathode materials like olivine phosphate. Polaron is a typical crystal defect caused by the integrated motion of lattice distortion and its trapping electrons. Research on the mechanism of polaron formation will provide theoretical guidance for the design of high-electronic-conductivity cathode materials and improvement of the electrochemical performance of LIBs. Theoretical calculation is a direct and important method to study polaron formation in a specific crystal material, because the presence of polarons and their formation mechanisms can be effectively verified through this method. In this article, we first introduce the basic physical concept of polarons and their dynamical model according to the Marcus and Emin-Holstein-Austin-Mott theories. A comparison of the general properties of large and small polarons, summarized in this chapter, reveals that small polaron formation more likely occurs in cathode materials. Moreover, the theoretical characterization, electrical impact, control and challenges of polarons are reviewed. Although a universal necessary and suitable condition for the theoretical characterization of polarons has not yet been found, we still propose three criteria that are proven to be feasible and practical for the theoretical identification of polarons when applied in combination. Experimental characterizations are also introduced briefly for reference, because the comparison with the experiment is suggested to be necessary and mandatory. The electrical impact caused by polarons results in low electronic conductivity, which has been broadly reported in layered, olivine, and spinel cathode materials. Doping can weaken the influence of polarons and, thus, significantly enhance the electronic conductivity, thereby becoming the most prevalent strategy for tuning polarons. Although theoretical calculations have been widely and effectively conducted in the study of polarons, some challenges may still be faced because of the intrinsic shortcomings of the traditional density functional theory, which need to be addressed. Finally, further research on polarons from the perspective of basic theory and practical applications is prospected.     

Regulation of Cathode‐Electrolyte Interphase via Electrolyte Additives in Lithium Ion Batteries

As the power supply of the prosperous new energy products, advanced lithium ion batteries (LIBs) are widely applied to portable energy equipment and large‐scale energy storage systems. To broaden the applicable range, considerable endeavours have been devoted towards improving the energy and power density of LIBs. However, the side reaction caused by the close contact between the electrode (particularly the cathode) and the electrolyte leads to capacity decay and structural degradation, which is a tricky problem to be solved. In order to overcome this obstacle, the researchers focused their attention on electrolyte additives. By adding additives to the electrolyte, the construction of a stable cathode‐electrolyte interphase (CEI) between the cathode and the electrolyte has been proven to competently elevate the overall electrochemical performance of LIBs. However, how to choose electrolyte additives that match different cathode systems ideally to achieve stable CEI layer construction and high‐performance LIBs is still in the stage of repeated experiments and exploration. This article specifically introduces the working mechanism of diverse electrolyte additives for forming a stable CEI layer and summarizes the latest research progress in the application of electrolyte additives for LIBs with diverse cathode materials. Finally, we tentatively set forth recommendations on the screening and customization of ideal additives required for the construction of robust CEI layer in LIBs. We believe this minireview will have a certain reference value for the design and construction of stable CEI layer to realize desirable performance of LIBs.     

Strategies for constructing manganese-based oxide electrode materials for aqueous rechargeable zinc-ion batteries

Commercial lithium-ion batteries(LIBs) have been widely used in various energy storage systems. However, many unfavorable factors of LIBs have prompted researchers to turn their attention to the development of emerging secondary batteries. Aqueous zinc ion batteries(AZIBs) present some prominent advantages with environmental friendliness, low cost and convenient operation feature. Mn O2electrode is the first to be discovered as promising cathode material. So far, manganese-based oxides have made...     

关于水系锌离子电池中无氧钒基正极材料的综述

水系锌离子电池具有功率密度高、环境友好、安全性高、低成本和锌资源丰富等优点，被认为具有潜力成为下一代电化学储能系统。然而，正极材料较差的电化学性能制约了水系锌离子电池的未来发展。尽管氧化锰、氧化钒、普鲁士蓝类似物、有机材料等多种材料已被广泛研究，设计具有高性能的理想正极材料仍面临着巨大挑战。无氧钒基化合物由于具有高的电导率、大的层间距、低的离子扩散势垒和高的理论比容量，受到越来越多的关注。本文总结了无氧钒基化合物的研究进展，包括电极材料的设计、改善其电化学性能的有效途径以及复杂的储能机制，提出了无氧钒基化合物目前面临的挑战和未来的发展前景，为进一步制备新型高性能钒基正极材料提供指导。     

镁离子电池正极材料研究进展

镁离子电池(MIBs)因镁资源储量丰富、体积能量密度大、金属镁空气中相对稳定等优势,被认为是具有大规模储能应用潜力的电池体系。然而,镁离子较高的电荷密度和较强的溶剂化作用导致其在正极材料中的可逆脱嵌和固-液界面上的离子扩散相当缓慢,严重影响了MIBs的电化学性能。近年来,人们针对MIBs正极材料开展了大量工作,取得了一定进展,但是还存在不少问题。本文先从MIBs体系的特点出发,阐述其优势和目前所面临的主要挑战,然后从无机正极材料和有机正极材料两方面展开,梳理并总结了各类正极材料的局限性及其解决策略,对优化方法和材料性能间的相关性进行归纳和讨论,为今后进一步发展具有优异电化学性能的MIBs正极材料提供可能的参考。     

A redox-active conjugated microporous polymer cathode for highperformance lithium/potassium-organic batteries

Organic redox-active materials have emerged as a class of electrode materials for rechargeable batteries due to their high redox activity,low cost,structure diversity and flexibility.However,the high solubility of organic small molecules in organic electrolytes commonly leads to the fast capacity decay with cycling.Herein,we report a redox-active conjugated microporous polymer of poly(pyrene-co-anthraquinone)(Py Aq)cathode material consisting of pyrene and anthraquinone units.Benefiting from the highly cross-linked polymer structure with insoluble nature in organic electrolytes,the high surface area and the plentiful redox-active carbonyl groups,the Py Aq cathode demonstrates outstanding electrochemical performances for both lithium-ion batteries(LIBs)and potassium-ion batteries(KIBs).Specifically,the Py Aq cathode for LIBs delivers a high reversible capacity of 169 m Ah g^-1 at the current density of 20 m A g^-1,a high rate capability(142 m Ah g^-1 at 1000 m A g^-1)and an excellent cycling stability for 4000 cycles.Additionally,the Py Aq cathode for KIBs also exhibits a high reversible capacity of143 m Ah g^-1 with a long cycling life over 800 cycles.The excellent electrochemical performance demonstrates that the newly developed Py Aq could be an attractive cathode material for the advanced energy storage technologies.     

锂离子电池低温性能改善研究进展

锂离子电池因其能量密度高,循环寿命长等优点已成为新型动力电池领域的研究热点,但其温度特性尤其是低温性能较差制约着锂离子电池的进一步使用. 本文综述了锂离子电池低温性能的研究进展,系统地分析了锂离子电池低温性能的主要限制因素. 从正极、电解液、负极三个方面讨论了近年来研究者们提高电池低温性能的改性方法. 并对提高锂离子电池低温性能的发展方向进行了展望.     

Fe2O3锂离子电池负极材料研究进展

Fe2O3锂离子电池负极材料因其具有的高能量密度而备受关注。但Fe2O3电极材料存在的如低导电性、充/放电过程中体积改变导致的循环稳定性差等问题限制其实际应用。介绍了高比表面积、结构稳定以及储锂动力学等因素对锂离子电池负极材料电化学性能的重要影响,综述电极活性材料纳米化、形貌控制和杂原子掺杂对Fe2O3负极材料电化学性能改善的相关研究进展,最后对Fe2O3电极材料的发展前景进行了展望。     

Hierarchical Surface Atomic Structure of a Manganese‐Based Spinel Cathode for Lithium‐Ion Batteries

The increasing use of lithium‐ion batteries (LIBs) in high‐power applications requires improvement of their high‐temperature electrochemical performance, including their cyclability and rate capability. Spinel lithium manganese oxide (LiMn₂O₄) is a promising cathode material because of its high stability and abundance. However, it exhibits poor cycling performance at high temperatures owing to Mn dissolution. Herein we show that when stoichiometric lithium manganese oxide is coated with highly doped spinels, the resulting epitaxial coating has a hierarchical atomic structure consisting of cubic‐spinel, tetragonal‐spinel, and layered structures, and no interfacial phase is formed. In a practical application of the coating to doped spinel, the material retained 90 % of its capacity after 800 cycles at 60 °C. Thus, the formation of an epitaxial coating with a hierarchical atomic structure could enhance the electrochemical performance of LIB cathode materials while preventing large losses in capacity.     

锂电池磷酸铁锂正极材料的结构与性能相关性的研究进展

磷酸铁锂(LiFePO_4)具有环境友好、价格便宜、安全性能好等优点,作为正极材料已经广泛应用于国内的电动车动力电池中;为了进一步提高电池的性能,需要对影响磷酸铁锂及同类材料(LiMPO_4 (LMP);M=Fe、Mn、Co、Ni及这些元素的混合)电化学性能的因素进行深入研究。本文从材料颗粒体相特征(相结构、掺杂、纳米化、缺陷和锂离子传输机制)、界面结构及在不同的电解质环境下的界面重构和电极结构与锂电池性能的构效关系等方面进行总结,系统化的阐述并总结了影响磷酸铁锂正极材料最新研究进展。     

Cathode pre-lithiation/sodiation for next-generation batteries

Electrochemical energy storage is playing a pivotal role in the global pursuit of a clean and sustainable energy future. Lithium-ion batteries (LIBs) are the state-of-the-art technology, but future energy requirements demand higher energy densities and a more diverse battery landscape to meet a wide variety of applications. Unfortunately, many next-generation LIB chemistries and beyond-LIB technologies suffer from large first-cycle irreversible capacity caused by active ion loss. The field of pre-lithiation/sodiation has recently emerged as researchers attempt to mitigate active ion loss and boost the energy density of next-generation LIBs and sodium-ion batteries. In this short review, we highlight recent advances in cathode pre-lithiation/sodiation using sacrificial additives and pre-lithiation/sodiation of cathode active materials.     

Nickel-Rich Layered Cathode Materials for Lithium-Ion Batteries

Nickel-rich layered transition metal oxides are considered as promising cathode candidates to construct next-generation lithium-ion batteries to satisfy the demands of electrical vehicles, because of the high energy density, low cost, and environment friendliness. However, some problems related to rate capability, structure stability, and safety still hamper their commercial application. In this Review, beginning with the relationships between the physicochemical properties and electrochemical performance, the underlying mechanisms of the capacity/voltage fade and the unstable structure of Ni-rich cathodes are deeply analyzed. Furthermore, the recent research progress of Ni-rich oxide cathode materials through element doping, surface modification, and structure tuning are summarized. Finally, this review concludes by discussing new insights to expand the field of Ni-rich oxides and promote practical applications.