Technology progress of cathode materials for lithium ion batteries

本文针对商业化锂离子电池正极材料,介绍了钴酸锂、镍钴锰三元材料、尖晶石锰酸锂、磷酸铁锂等正极材料的优缺点、市场现状,以及我国正极材料的技术和产业现状。对行业存在的共性问题,如产品品质差,技术实力不足进行了分析。展望了产业未来发展趋势,并提出了增加技术投入、加强产学研协同和高端装备应用等建议。     

Research progress on cathode materials for high energy density lithium ion batteries

便携式电子设备的微型化、轻量化与电动汽车、电网储能设备的飞速发展,对高能量密度的锂离子电池的研发和性能表现提出了越来越高的要求。锂离子电池正极材料是锂离子电池的核心,其提供锂离子并参与电化学反应,因此改善正极材料性能是提高锂离子电池能量密度的关键。人们需要进一步研究开发成本较低、安全性更好的高能量密度新型锂离子电池正极材料。本文主要从提升正极材料的比容量和工作电压两方面介绍三元、富锂锰基材料和高电位镍锰酸锂等高比能量正极材料的介尺度结构设计、制备与性能调控研发进展。     

Structure and properties of cathode materials for ion batteries

近年来,可充电电池以其成本低廉、操作简单、安全环保等优点引起了不少研究者的关注。与锂离子电池相比,钠、钾、镁、锌和铝等离子电池在成本和安全等方面表现出独特的优势,为电池型储能系统（BESS）和电动汽车（EVs）的发展提供了新的思路。正极材料作为离子电池的重要组成之一,其性能的优劣将直接影响整个电池系统的工作状况。本文将介绍离子电池正极材料在容量、循环寿命和能量密度方面的最新进展,以及离子的储存机制。此外,探讨了材料结构和性能间的关系,总结了各种改善离子储存性能的方法,从而使低成本的离子电池更接近可持续大规模储能系统的应用。     

A review on lithium iron phosphate cathode materials

目前全球高动力锂离子电池系统的发展主要集中在锂锰电池,锂钴镍锰电池以及锂铁电池,其中磷酸亚铁锂材料具有高电容量,高放电功率,极佳的长循环寿命以及良好的热稳定性与高温性能等优点,已成为动力锂离子电池首选的高安全性正极材料.然而,磷酸亚铁锂材料在工业化量产时,必须解决电池芯加工性差及材料一致性不佳等问题,作者曾结合多项新颖观念与技术于磷酸亚铁锂材料制做过程,在粉体表面涂布碳层,在晶体内部掺杂金属,分别改善材料电导率与锂离子扩散速度以及有效地控制碳含量,粉体比表面积,碳层均匀性,粒径大小与分布,制备出高质量磷酸亚铁锂产品.该文将回顾并探讨上述研发工作的一些重要结果.     

Theoretical evaluation of high-energy lithium metal phosphate cathode materials in Li-ion batteries

Lithium metal phosphates (olivines) are emerging as long-lived, safe cathode materials in Li-ion batteries. Nano-LiFePO₄ already appears in high-power applications, and LiMnPO₄ development is underway. Current and emerging Fe- and Mn-based intercalants, however, are low-energy producers compared to Ni and Co compounds. LiNiPO₄, a high voltage olivine, has the potential for superior energy output (>10.7 Wh in 18650 batteries), compared with commercial Li(Co,Ni)O₂ derivatives (up to 9.9 Wh). Speculative Co and Ni olivine cathode materials charged to above 4.5 V will require significant advances in electrolyte compositions and nanotechnology before commercialization. The major drivers toward 5 V battery chemistries are the inherent abuse tolerance of phosphates and the economic benefit of LiNiPO₄: it can produce 34% greater energy per dollar of cell material cost than LiAl_0.05Co_0.15Ni_0.8O₂, today's “standard” cathode intercalant in Li-ion batteries.     

全固态锂离子电池关键材料研究进展

全固态锂离子电池采用固态电解质替代传统有机液态电解液,有望从根本上解决电池安全性问题,是电动汽车和规模化储能理想的化学电源。为了实现大容量化和长寿命,从而推进全固态锂离子电池的实用化,电池关键材料的开发和性能的优化刻不容缓,主要包括制备高室温电导率和电化学稳定性的固态电解质以及适用于全固态锂离子电池的高能量电极材料、改善电极/固态电解质界面相容性。本文以全固态锂离子电池关键材料为出发点,综述了不同类型的固态电解质和正负极材料性能特征以及电极/电解质界面性能的调控和优化方法等,阐述了未来全固态锂离子电池关键材料的发展方向以及界面问题的解决思路,为探索全固态锂离子电池产业化前景奠定基础。     

Research progress in blending modification cathode materials for lithium ion batteries

本文简述了国内外锂离子电池正极材料共混改性的研究进展。正极材料是锂离子电池重要组成部分,是决定锂离子电池能量密度和成本的关键因素。共混改性具有制备工艺简单、材料性能一致性容易控制、综合成本较低等优点,在钴酸锂、锰酸锂、磷酸铁锂和三元材料电池制造中得到应用。国内外通过对正极材料共混改性机理研究,发现共混改性是材料改善电化学性能、降低成本、提升安全性能的有效途径,并有望发展成为依据材料特性指导锂离子电池高性能电极设计的重要方法。同时在正极材料共混改性方面亟需加强共混材料物性匹配、充放电机制选取、共混工艺研究,该方法也为高镍、富锂锰基等新一代正极材料工业化应用提供了工艺参考。     

Progress in magnetic resonance research of important cathode materials in lithium ion batteries

锂离子电池得到了快速发展,并改变了我们的生活。锂离子电池正极材料的研究是提高电池性能的关键;而理解正极材料的性能与结构之间的关系、阐释正极材料的电化学反应机理（尤其是性能衰减与失效机理）有助于提高材料的能量密度和功率密度。磁共振技术（含核磁共振和顺磁共振）在过去三十多年的研究中不断进步,逐渐成为研究正极材料构效关系的关键技术之一。本文总结了几个重要的已经商业化的正极材料（LiCoO₂、NCA、NMC和LiFePO₄）的磁共振研究进展,展示了核磁共振、顺磁共振在正极材料构效关系研究中的重要作用;尤其值得一提的是原位技术的发展在电化学反应机理中逐渐显示出其重要性。本文有助于了解磁共振技术在电池材料研究中的重要价值,并进一步推动磁共振技术的发展。     

Interpretation of cathode material standards for lithium ion batteries

随着应用领域的不断拓宽,近年来锂离子电池行业呈现稳步快速增长态势,其正极材料迎来了前所未有的发展机遇。我国在锂离子电池正极材料的开发和产业化方面具有得天独厚的优势,拥有完善的产业链和可持续发展的良好势头,市场上出现了越来越多的正极种类和产品类型。本文介绍了国内锂离子电池正极材料标准的现状,对比分析了不同类别正极材料的关键技术指标要求,解读了指标出现差异的原因,并指出了个别标准的不足之处,对今后的标准化工作提出了建议。     

Technology review of anode materials for lithium ion batteries

本文综述了目前已经商业化生产的锂离子电池负极材料,主要包括天然石墨,人造石墨,硬碳,软碳,Li₄Ti₅O₁₂材料,硅基材料等.详细阐述了这些负极材料的优缺点,并对它们的性能优劣进行了对比,给出了各自具有代表性的充放电曲线.概述了各类负极材料目前的国内外市场状况,并对未来几年锂离子电池负极材料市场的发展趋势进行了预估.介绍了各类负极材料的产业化现状,包括主流生产工艺,产品应用领域,行业领先企业等,总结了各类负极材料,尤其是天然石墨和人造石墨在中国的早期研发历史,并整理了各类负极材料在国内最早发表的文章和专利.最后概述了目前整个锂离子电池负极材料行业存在的一些问题,讨论了目前锂离子电池负极材料的发展思路,并展望了未来的技术发展趋势.     

Synthesis and electrochemical characterization of amorphous Li-Fe-P-B-O cathode materials for lithium batteries

Various types of amorphous Li-Fe-P-B-O were investigated for use as a cathode material. The samples were prepared by the melt quench technique with a single roll. The samples had monotonically decreasing charge-discharge profiles peculiar to amorphous materials, and were between 76 and 119 mAh g⁻¹. The electrochemical performance of these amorphous Li-Fe-P-B-O materials improved with increasing boron ratio, improving from 85 to 119 mAh g⁻¹. Although the redox potentials of amorphous Li-Fe-P-O did not shift with changing P/Fe ratio, those of amorphous Li-Fe-P-B-O did shift with changing B/P ratio. The redox potentials of the Li-Fe-P-B-O in the ratios of 2/1/2/0, 2/1/1/1, 2/1/0.5/1.5, and 2/1/0/2 were approximately 3.1, 2.9, 2.6, and 2.2 V vs. Li/Li⁺, respectively. This demonstrates that the redox potentials of amorphous polyanionic materials can be tuned by adjusting the electronegativity of the glass former, such as phosphorus and boron.     

Research progress of cathode materials for lithium-sulfur batteries

锂硫电池作为一种非常有前途的高能化学电源,随着电动汽车和便携式电子设备的发展,因其高理论比容量（1675 mA·h/g）和高理论能量密度（2600 W·h/kg）引起了人们的广泛关注。然而,锂硫电池发展过程中的一些挑战不可避免,包括硫较低的离子和电子导电性,较差的循环性以及生成的多硫化物易溶于有机溶剂等缺点,制约了锂硫电池的发展。本文结合近年来锂硫电池正极材料的研究进展,简要阐述了锂硫电池正极材料的研究现状、问题及面临的挑战。锂硫电池由于其发展中面临技术瓶颈难以突破,导致现在还无法大规模的应用,因而对其性能的改进也就成了当今的研究热点。硫电极材料电导率低、循环性能差,可以通过碳包覆或者掺杂改善材料性能。然而由于成本和技术问题,大部分锂硫电池正极材料目前还主要处于研究试验阶段。因此,在提高材料性能的前提下,通过碳包覆或者掺杂改善工艺,探索一条适合工业化生产的道路是下一阶段研究的重点。     

Characterisation of charge and discharge behaviour of lithium ion batteries with olivine based cathode active material

This paper gives insight to the physical processes taking part during the two-phase transition in lithium intercalation compounds. The behaviour of olivine based electrodes is in the special focus of this work. These electrodes exhibit phase juxtaposition within the electrode particles over a wide state of charge (SOC) range. Measurements were made to explore effects related to the formation of distinct phase sequences within the particles. Asymmetric charge characteristics, a load history dependency of the internal resistance and a voltage effect related to the disappearance of certain phase regions (the later on called vanishing phase effect) were identified. Moreover, these measurements give evidence to the existence of stable phase regions inside the electrode active material. An intuitive model is given to visualize the phase regions within spherical olivine particles. Therefore an analytical approach is developed in order to take the geometry of the particles, the ion permeability as well as the size distribution of the particles in consideration. According to the developed approach and the obtained measurement results, an enhanced cell equivalent electrical circuit is evaluated, considering phase shell development effects.     

High performance silicon carbon composite anode materials for lithium ion batteries

Silicon and silicon containing compounds are attractive anode materials for lithium batteries because of their low electrochemical potential vs. lithium and high theoretical capacities. In this work the relationship between the electrochemical performance of silicon powders and their particle sizes was studied. It is found that the material with nano particle sizes gives the best performance. New silicon/carbon composite anode materials were synthesized and their structures and electrochemical performance were investigated. The results of these studies are reported in this paper.     

Recent developments in cathode materials for lithium ion batteries

One of the challenges for improving the performance of lithium ion batteries to meet increasingly demanding requirements for energy storage is the development of suitable cathode materials. Cathode materials must be able to accept and release lithium ions repeatedly (for recharging) and quickly (for high current). Transition metal oxides based on the α-NaFeO₂, spinel and olivine structures have shown promise, but improvements are needed to reduce cost and extend effective lifetime. In this paper, recent developments in cathode materials for lithium ion batteries are reviewed. This includes comparison of the performance characteristics of the promising cathode materials and approaches for improving their performances.     

Progress of electrolyte additives for high-capacity power lithium ion batteries

动力电池是新能源汽车的核心部件,而电解液是制约动力电池发展的关键。电解液一般由碳酸酯类溶剂、锂盐和添加剂组成,其性质对电池的高低温、倍率、寿命等性能有显著影响。高比能动力电池所需电解液的主要开发策略是利用功能添加剂在电池正、负极同时形成稳定的保护膜,同时稳定界面。文章回顾了近年来匹配高压正极材料和高容量硅碳负极材料所需添加剂的组成和基本功能,论述了添加剂作用机理和发展趋势,认为300 W·h/Kg高能量密度电池电解液的关键在于开发新型多功能添加剂。     

Recent progress in electrode materials for aqueous lithium-ion batteries

水系锂离子电池是以水溶液为电解质的二次电池,它克服了传统有机体系电池电解液昂贵,有毒,易燃,离子电导率低,制作成本高等缺点,成为继风能,太阳能后最具发展潜力的绿色能源之一.本文归纳了近年来国内外水系锂离子电池正负极材料的研究进展,介绍了各种电极材料存在的主要问题(如电极材料在电解液中的溶解,电解液中质子活性大导致电极材料发生副反应等)以及改性方法,并提出对电极材料进行修饰是水系锂离子电池未来的发展趋势.     

High specific capacity composite cathode materials for lithium-sulfur batteries

Li与S完全反应生成Li₂S时,单质硫正极的理论比容量为1675 mA·h/g,比LiFePO₄,LiCoO₂等正极材料的比容量高很多.单质S价格低,无毒,是一种理想的正极材料,然而其导电性较低,循环比容量衰减较快,因此需要改善S正极材料的导电性来提高其电化学性能.本文综述了硫基复合正极材料的制备方法,结构与形貌,电化学性能.探讨了S与多孔碳,碳纳米管,石墨烯和聚吡咯等复合的正极材料的电化学性能,并对硫基正极材料的发展趋势进行了展望.     

Improving electrochemical properties and structural stability of lithium manganese silicates as cathode materials for lithium ion batteries via introducing lithium excess

The serious capacity decay caused by structural amorphization is still a major issue for polyanion-type lithium manganese silicates (Li₂MnSiO₄) as cathode material for lithium ion batteries. In this work, a new strategy for alleviating the structural instability via the introduction of excess lithium into the host crystal lattice is provided. A comprehensive study demonstrates that the required energy for the extraction/insertion of lithium ions into host crystal lattice was decreased as a result of changed local environment of cations in the compound after the excess lithium occupancy in lattice. Importantly, it was found that Li-rich samples deliver higher reversible capacity and increased average potential than pristine sample, indicating the improved energy density of polyanion-type Li_{2 + 2x}Mn_{1 − x}SiO₄/C_. Additionally, the structure of Li2.2 sample was kept intact, while the Li2.0 sample was transformed to amorphous state at 200 mA h g⁻¹ during the initial charging process by controlling the charge cut-off potential. As expected, the introduction of a certain amount of excess lithium into Li₂MnSiO₄ is explored as a route to achieving increased capacity with more movable lithium, while maintaining its structural stability and cyclic stability.     

Synthesis and electrochemical performance of Li2CoSiO4 as cathode material for lithium ion batteries

Li₂CoSiO₄ has been prepared successfully by a solution route or hydrothermal reaction for the first time, and its electrochemical performance has been investigated primarily. Reversible extraction and insertion of lithium from and into Li₂CoSiO₄ at 4.1 V versus lithium have shown that this material is a potential candidate for the cathode in lithium ion batteries. At this stage reversible electrochemical extraction was limited to 0.46 lithium per formula unit for the Li₂CoSiO₄/C composite materials, with a charge capacity of 234 mAh g⁻¹ and a discharge capacity of 75 mAh g⁻¹.