Research progress on the nano-Si/C materials with high capacity for Lithium-iom battery

纳米硅碳材料主要成分为纳米硅与碳材料,纳米硅具有较小的颗粒尺寸,其储锂容量较高,碳材料具有较高的电子电导,为复合材料提供较好的电子通道;同时将碳与硅材料复合后能缓和硅材料体积形变带来的应力变化;此外,碳作为包覆材料能有效稳定电极材料与电解液的界面,使SEI膜稳定生长。因此,硅碳复合材料有望替代石墨成为下一代高能量密度锂离子电池负极。本文简要介绍了纳米先导专项硅负极研究团队在纳米硅碳材料方面的研究进展。通过持续的研发与技术更新,目前低容量复合材料（380～450 mA·h/g）的反弹系数、效率、压实密度、加工性能皆不亚于目前商品石墨的水平;在高容量及超高容量材料（500～2000 mA·h/g）方面,通过精细的结构设计,循环性能和倍率性能等得到了较大提升。     

Research progress on capacitive lithium-ion battery

锂离子电池具有高的能量密度,而超级电容器则以高功率密度和长循环寿命为突出优势。电容型锂离子电池是在锂离子电池的正极中加入部分电容炭材料,在不显著降低能量密度的情况下,大幅度改善锂离子电池的功率特性和循环寿命,从而实现电容与电池技术的融合。本文综述了国内外近年来在电容型锂离子电池领域的最新研究进展,介绍了主要的电容型锂离子电池体系及其性能特点,并对其未来发展方向进行了展望。     

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。     

Research progress on electrolyte additives for high voltage lithium-ion batteries

普通锂离子电池在高电压下的氧化分解限制了高压锂离子电池的发展,为了解决这一问题,可以设计、合成新型的耐高压电解液;寻找合适的电解液添加剂,然而从经济效益考虑,发展合适的电解液添加剂来稳定电极/电解液界面更加受到研究者们的青睐。本文综述了最近几年在高压锂离子电池电解液添加剂方面的研究进展,并按照添加剂的种类将其分为6部分进行探讨：含硼类添加剂、有机磷类添加剂、碳酸酯类添加剂、含硫添加剂、离子液体添加剂及其它类型添加剂。分别对这些添加剂的作用机理、作用效果进行了阐述,展望了添加剂在高压锂离子电池中的发展前景及未来研究方向。     

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。     

Progress in the modification of lithium-rich manganese-based layered cathode material

纯电动汽车以及混合动力汽车的快速发展使得研发高能量密度的锂离子电池正极材料迫在眉睫。层状富锂锰基正极材料比容量可达250 mA·h/g,平均放电电压高于3.5 V,电化学特征明显优于钴酸锂和磷酸铁锂等传统的正极材料,是实现300 W·h/kg动力锂离子电池极具潜力的正极材料。不过,此类材料循环性能不佳,并伴随严重的电压衰退现象,主要原因是随着循环的进行材料表面结构重组,晶体结构发生了由层状结构向尖晶石结构的不可逆转化,导致锂离子迁移阻力增大,进而严重影响其电化学性能。为解决这些问题,近年来研究人员开展了大量工作,本文主要从体相掺杂、表面包覆、材料微观结构设计以及晶面调控4个方面详细评述了锂离子电池富锂锰基正极材料改性技术的研究进展。     

Thermodynamic analysis of high energy density conversion type cathode materials for Na- and K-ion batteries

Conversion-type materials attract increasing attention for rechargeable batteries because of their high energy density compared with intercalation-type materials. However, the development of conversion materials for sodium and potassium ion batteries is in its beginnings, and a few materials have been studied. In this study, high-throughput computational screening was performed to discover high energy density conversion cathode materials for sodium and potassium batteries. Conversion reactions of cathode materials were examined using the Materials Project database. The reaction voltage curves as a function of specific capacity were obtained using grand potential phase diagram. The calculation results indicated that fluorides, chlorides, bromides, and oxides are promising conversion cathode materials, exhibiting high reaction potential and capacity. The average reaction potentials of sulfides, selenides, phosphides, and nitrides indicated that they are not appropriate materials for conversion cathodes.     

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。     

Research progress on inorganic additives for lithium-ion battery electrolytes

总结了无机添加剂用于锂离子电池电解液的发展概况和最新的一些研究进展,结合其作用机制或作用效果将其具体分成三类进行探讨:无机成膜添加剂;研究阴极活性物质溶解与容量衰减关系的过渡金属盐添加剂;其它种类添加剂,如除去电解液中的HF,抑制锰沉积对石墨负极性能的影响和增加电解液电导率等.详细阐述了这些无机添加剂的作用机理,作用效果以及应用的局限性,并分析了这类添加剂的未来前景.     

Multi-functional additive PFPN for rechargeable lithium sulfur battery with composite cathode materials

由于具有极高的比容量和丰富的硫资源储量,锂硫电池已成为下一代可充电池研究的热点之一。但锂硫电池中存在较大的安全性隐患,这将阻碍其实际应用。一种高效的阻燃添加剂,乙氧基五氟环磷腈（PFPN）被首次用于锂硫电池。添加5%质量分数的PFPN使得高度易燃的碳酸酯电解液完全不燃,同时减小极化电压,并显著提高硫基复合材料的倍率性能。上述结果表明,PFPN是一种适用于可充锂硫电池的多功能添加剂。     

Inhibition of solid electrolyte interface formation on cathode particles for lithium-ion batteries

Thermal reactions between cathode particles (LiNi_0.8Co_0.2O₂, LiCoO₂, LiMn₂O₄ and LiFePO₄) and ternary electrolyte (1.0 M LiPF₆ in 1:1:1 diethyl carbonate/dimethyl carbonate/ethylene carbonate) with or without the thermal stabilizing additive dimethyl acetamide (DMAc) have been investigated. Ternary electrolyte reacts with the surface of lithiated metal oxides (LiNi_0.8Co_0.2O₂, LiCoO₂ and LiMn₂O₄) upon storage to corrode the surface and generate a complex mixture of organic and inorganic surface species, but the bulk ternary electrolyte does not decompose. There is little evidence for reaction between the surface of carbon coated LiFePO₄ and ternary electrolyte upon storage at elevated temperature (>60 °C), but the bulk ternary electrolyte decomposes. Addition of DMAc to ternary electrolyte reduces the surface corrosion of the lithiated metal oxides and stabilizes the electrolyte in the presence of LiFePO₄.     

Research progress of high rate Li-ion battery materials

电动汽车行业迅速发展,高倍率的锂离子电池是其关键,因此需要不断开发适用高倍率充放电的电池材料。本文简要综述了高倍率锂离子电池正极材料、负极材料、隔膜和电解液方面的研究进展,并对高倍率锂离子电池材料发展进行了展望。     

Li2MnO3 based Li-rich cathode materials: towards a better tomorrow of high energy lithium ion batteries

Abstract

Li₂MnO₃ based layered Li-rich materials as promising cathode candidates of Li ion batteries (LIBs) have attracted much recent attention mainly owing to their superior high specific capacity and high working voltage. To date, although researchers have put much effort to this family of materials, there are still a number of issues under debates in the fundamental understanding of the crystal structures and the electrochemical reaction mechanisms, before the materials can be ready for practical applications. In this review article, we address the recent progress of this group of Li-rich cathode materials with a good hope to better understanding of the relationships among composition, crystal structure and electrochemical reaction mechanisms. In addition, the use of advanced microscopic characterisation and the strategies of novel material designs will also be discussed for better cathode design for LIBs.     

Research progress on sulfur cathode of lithium sulfur battery

锂硫电池具有能量密度高、原料低廉、绿色环保等优势,已成为下一代高性能二次电池的研究热点,但是活性材料利用率低、容量衰减较快、自放电严重等问题,极大地阻碍了该电池的实用化进程。正极是电池的核心部件,要实现锂硫电池的性能提升,必须对硫正极的组分结构进行合理的设计与构建。本文首先分析锂硫电池的工作原理、存在问题及解决途径,然后分别从硫正极的活性材料、集流体、表面涂层、黏结剂、添加剂等5个方面对当前的研究现状进行总结,最后对其未来的发展前景做出展望,文章指出,硫正极更应关注真实的能量密度水平,而锂硫电池的研究视野不应局限于正极材料。     

MnO/C core-shell nanorods as high capacity anode materials for lithium-ion batteries

MnO/C core-shell nanorods were synthesized by an in situ reduction method using MnO₂ nanowires as precursor and block copolymer F127 as carbon source. Field emission scanning electron microscopy and transmission electron microscopy analysis indicated that a thin carbon layer was coated on the surfaces of the individual MnO nanorods. The electrochemical properties were evaluated by cyclic voltammetry and galvanostatic charge-discharge techniques. The as-prepared MnO/C core-shell nanorods exhibit a higher specific capacity than MnO microparticles as anode material for lithium ion batteries.     

Research progress of high safety flame retardant electrolytes for lithium-ion batteries

商品锂离子电池在机械冲击、热冲击和过充短路等滥用条件下易发生起火燃烧甚至爆炸。为了解决这一安全性问题,需要开发高安全性阻燃电解液取代传统易燃烧的碳酸酯电解液。本文综述了高安全性阻燃电解液的研究进展,首先介绍了燃烧机理、阻燃机理和阻燃测试方法,再阐述锂离子电池对阻燃电解液的性质要求,并对阻燃电解液进行分类探讨,包括阻燃添加剂、阻燃溶剂（共溶剂）、高浓度阻燃电解液、离子液体和阻燃型凝胶聚合物电解质。重点对这些高安全性阻燃电解液的配方、阻燃效果、适用的电池体系进行详细阐述。最后对高安全性阻燃电解液未来的研究方向进行展望。     

Research progress on biomass-derived carbon electrode materials for electrochemical energy storage and conversion technologies

Electrochemical energy technologies such as fuel cells, supercapacitors, and batteries are some of the most suitable energy storage and conversion devices to meet our needs proving the future generation’s equitable opportunity to meet their own needs. For this purpose, an earth-abundant precursor such as biomass is the best candidate for the synthesis of the next generation of low-cost and green electrode materials. This review summarizes the most recent progress in biomass-derived carbons for use in fuel cells, supercapacitors and lithium-ion batteries, the physical-chemical properties, desired features, performances, and limitations for electrochemical energy technologies. Several thermochemical treatments such as chemical activation, template methods, doping and hydrothermal treatments have been reviewed. Finally, we provide the reader with comprehensive information of the challenges, future research efforts, advantages, limitations and opportunities which will be a fundamental insight for the future design of biomass-derived carbon electrode materials for electrochemical storage and conversion systems.     

High voltage spinel cathode materials for high energy density and high rate capability Li ion rechargeable batteries

We have synthesized LiMn_1.5Ni_0.4Cr_0.1O₄ cathode material for high energy density Li ion rechargeable batteries using sol-gel method. The synthesized materials were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy, cyclic voltammetry and charge-discharge characteristics. It was found that phase pure materials were obtained an annealing temperature of 875 °C for 15 h. The maximum discharge capacity at a constant charge-discharge current rate 1C, 0.5C, and 0.2C were found to be about 99 mAh g⁻¹, 110 mAh g⁻¹, and 131 mAh g⁻¹, respectively. The capacity retentions after 50 charge-discharge cycles were found to be about 99%, 97%, and 97.3% at discharge current rates of 0.2C, 0.5C, and 1C. The stable electrochemical behavior of the above cathode material even at high C rate, showed that it could be used for high energy density and high rate capability Li ion rechargeable batteries.     

Recent progress of electrode materials for room-temperature sodium-ion stationary batteries

随着风能、太阳能等可再生能源的不断发展,储能作为影响其发展的关键技术越来越受到人们的关注。在储能领域,锂离子电池以高能量密度、长循环寿命、高电压等诸多优点在电子领域已得到广泛的应用,并成为未来电动汽车动力电池的最佳选择。但因锂资源储量有限、分布不均匀,而且原材料成本比较高,所以锂离子电池在电网大规模储能方面的应用遇到了瓶颈。与锂相比,钠不但具有与锂相似的物理化学性质,更具有资源丰富、分布广泛、原料成本低廉等优势。近些年室温钠离子电池再次引起了人们的研究兴趣,特别是在电网储能方面表现出极大的应用潜力。虽然目前已报道了多种钠离子电池电极材料,但大都离实用化以及进一步产业化尚有一定的距离。本文重点介绍一些性能较为突出的室温钠离子电池电极材料,并指出要实现钠离子电池的产业化,需要开发空气中稳定、高安全、高容量、高倍率、循环稳定、低成本的新型正、负极材料。     

Surface homogenizing heterostructure coatings induced by Ti3C2Tx MXene for enhanced cycle performance of lithium-rich cathode materials

The layered lithium-rich manganese-based cathode material (Li_1.2Mn_0.54Co_0.13Ni_0.13) has the significant advantage of high specific capacity, but this material also suffers serious defects, including severe capacity attenuation and voltage attenuation during the cycle. At present, most researchers have been working to optimize the cycle performance of lithium-rich materials. In this work, we propose a surface homogenizing heterostructure coating induced by MXene modification to reduce capacity reduction and voltage decay. It can be found that the initial Coulombic efficiency (ICE) increases from 77.2% for the bare electrode Li_1.2Mn_0.54Co_0.13Ni_0.13 (LMO) to 85.5% for 1.4 wt% MXene (Ti₃C₂T_x, T_x represents the surface terminations: OH, O, F) modified lithium-rich (TO2). Furthermore, the discharge specific capacity of the electrode at 5 C rate increased from 160.7 mAh g⁻¹ for LMO to 200.6 mAh g⁻¹ for TO2. More prominently, the outstanding cycle stability with capacity retention rate is 82.1% for TO2 after 200 cycles, while only 64.7% for LMO, and the average discharge voltage dropped from 0.788 to 0.468 V. In addition, the mechanism for improving the electrochemical performance is systematically studied.