金属锂枝晶生长机制及抑制方法

金属锂负极以极高的容量（3860 mAh ·g^-1）和最负的电势（-3.040 V vs标准氢电极）而被称为二次锂电池"圣杯"电极。以金属锂为负极的金属锂电池是极具前景的下一代高比能电池（比如锂硫和锂氧电池等）。然而,在锂离子反复沉积和析出过程中,金属锂负极表面容易生长出锂枝晶,并发生粉化,大大降低了电池的利用率,造成安全隐患,缩短电池使用寿命。本综述针对金属锂的枝晶问题开展评述。首先介绍金属锂负极的工作原理和存在的挑战;其次,评述金属锂负极的枝晶生长模型;再次,总结近年来针对抑制金属锂负极枝晶生长的研究进展。最后,总结全文并对金属锂负极的研究进行了展望。该综述尝试总结金属锂负极近些年在理论和技术上的进步,并为金属锂电池的实用化研究提供借鉴。     

球形碳颗粒用于高效稳定“金属锂储藏室”

<正>随着便携式电子、电动车和储能电网的快速发展,亟需开发高能量密度的二次电池体系。金属锂具有高的理论比容量(3860mAh?g~(-1)),低的密度(0.59g?cm~(-3))和最低的还原电位(相对于标准氢电位为-3.04V)。因此,利用金属锂代替传统石墨为负极获得的金属锂二次电池是一种极具应用前     

高能量密度锂二次电池电极材料研究进展

锂离子电池是目前广泛应用的高能量密度小型二次电池,但随着其应用领域突飞猛进的发展,迫切需要进一步提高其能量密度.本文介绍了近年来高能量密度锂离子电池正、负极材料及新型高能量密度锂二次电池体系方面的研究进展;结合本实验室的研究工作,着重介绍了高容量正、负极材料的选择、微纳结构设计、表面包覆和合成策略;讨论了锂硫电池、锂空气电池等高比能金属锂二次电池的未来发展方向.     

金属锂二次电池锂负极改性

本文综述了金属锂二次电池中提高锂负极性能的研究进展。分别介绍了以下改性方法:对金属锂表面进行预处理,使其表面预先形成性能良好的固体电解质界面膜,或直接在其表面制备保护膜;在电解液中加入添加剂对锂电极进行表面改性;采用新型有机溶剂、离子液体、聚合物电解质、玻璃态固体电解质、塑晶固体电解质等电解质体系提高界面相容性;改进金属锂电极的制备工艺,如制备金属锂粉末多孔电极和电沉积锂电极、制备全固态薄膜锂电池以及利用物理方法处理锂电极。并在此基础上对今后的发展趋势进行了展望。     

天然气焦炭的嵌锂特性研究

锂离子电池的研究与开发具有诱人的商业前景．以金属锂为负极的锂二次电池存在着充放电循环寿命短和使用安全性能差等诸多问题，解决的途径之一是采用嵌锂化合物替代金属锂作为负极材料．其中，以具有贮锂功能的碳素材料作为负极的锂离子电池，不仅具有较高的电容量和较长...     

二次离子电池高比容量负极碳载体的研究进展

二次离子电池商业化负极石墨的比容量已接近理论比容量. 合金型负极和金属负极因具有高比容量而受到广泛关注, 但其循环性能差和安全性问题限制了实际应用, 据此提出载体设计策略. 碳材料具有来源广泛、 易于调控等特性, 常用作二次离子电池高比容量负极的载体. 本文从碳载体的孔结构、 比表面积、 电子导电率、 离子导电率、 杂原子掺杂和界面修饰的角度出发, 综述了其在硅基、 磷基、 锗基、 锡基负极以及金属锂、 钠等负极中的研究进展, 展望了碳载体的发展前景和方向.     

人工界面层在金属锂负极中的应用

金属锂具有极高的比容量(3860 mAh·g^?1)和最低的电化学反应电位(相对标准氢电位为?3.040 V),被认为是高能量密度二次电池最具潜力的负极材料。然而金属锂负极界面稳定性差、不可控的枝晶生长、沉积/剥离过程中巨大的体积变化等严重阻碍了金属锂负极的商业化应用。在金属锂表面构建一层物理化学性质稳定的人工界面保护层被认为是解决金属锂负极界面不稳定和枝晶生长,缓解体积膨胀带来的界面波动等一系列问题的有效手段。本综述依据界面传导性质,从离子导通而电子绝缘的人工固态电解质界面(SEI)层、离子/电子混合传导界面、纳米界面钝化层三个部分对人工界面保护层进行了归纳总结。分析了人工界面保护层的物质结构与性能之间的构效关系,探讨了如何提高人工界面保护层的物理化学稳定性、界面离子输运、界面强度与柔韧性、界面兼容性等。最后,指出用于金属锂负极的人工界面保护层目前面临的主要挑战,并对其未来的发展进行了展望。     

热熔灌输法制备三维骨架支撑金属锂复合负极

金属锂因具有极高的理论比容量(3860 mAh/g)和最低的电化学势(相对于标准氢电极为-3.04 V),被认为是下一代高比能锂离子电池的首选负极材料。然而,金属锂负极在电池循环过程中发生的刺状枝晶生长和体积变化等问题严重阻碍了其产业化应用进程。近年来研究表明,通过在金属锂中引入具有三维(3D)结构的宿主骨架,不但能有效抑制锂枝晶的生长,而且可以缓解金属锂负极的体积变化,从而提高金属锂电池的循环性能与安全性。因此,设计3D骨架/金属锂复合负极被认为是一种能有效解决金属锂问题的新兴策略。本文综述了热熔灌输法制备3D骨架/金属锂复合负极的研究进展。首先讨论了当前基于3D骨架的预存金属锂技术,然后着重分析了热熔灌输策略中3D骨架锂润湿性的影响因素,以及不同3D骨架修饰特征和改性方法。最后对3D骨架/金属锂复合负极和热熔灌输策略现存问题进行了总结并提出未来的发展方向。     

二次金属离子电池的研究现状*

二次电池是应用范围广泛,发展前景广阔的电化学储能器件。综述了二次金属离子电池体系的基本工作原理和研究现状,对二次金属离子电池储能技术的发展做出了展望。     

非水溶剂Li-O_2电池锂负极研究进展（英文）

非水溶剂Li-O_2电池因其高的理论能量密度,近年来备受关注。非水溶剂Li-O_2电池的典型结构为金属锂负极、含Li+的非水溶剂电解液和多孔氧气正极。目前,多数Li-O_2电池研究集中在正极的氧气电极反应;金属锂负极极强的还原性导致的副反应使Li-O_2电池中的化学和电化学反应变得更为复杂。因为,电解液和从正极扩散来的O_2都会与金属锂发生反应;锂负极上生成的副反应产物同样会扩散到正极一侧,干扰正极的O_2反应。此外,锂负极上可能生成锂枝晶,降低电池的安全性能,进而阻碍Li-O_2电池的实用化。因此,研究并解决锂负极的电化学稳定性和安全问题迫在眉睫。本文综述了近年来国内外在非水溶剂Li-O_2电池锂负极保护和修饰方面的最新研究进展,包括:可替代的对/参比电极的选择、电解液和添加剂、复合保护层与隔膜的研究、先进实验技术的开发与应用、并针对未来非水溶剂Li-O_2电池的发展进行了展望。     

Enabling High‐Voltage Lithium Metal Batteries by Manipulating Solvation Structure in Ester Electrolyte

Lithium metal is an ideal electrode material for future rechargeable lithium metal batteries. However, the widespread deployment of metallic lithium anode is significantly hindered by its dendritic growth and low Coulombic efficiency, especially in ester solvents. Herein, by rationally manipulating the electrolyte solvation structure with a high donor number solvent, enhancement of the solubility of lithium nitrate in an ester‐based electrolyte is successfully demonstrated, which enables high‐voltage lithium metal batteries. Remarkably, the electrolyte with a high concentration of LiNO₃ additive presents an excellent Coulombic efficiency up to 98.8 % during stable galvanostatic lithium plating/stripping cycles. A full‐cell lithium metal battery with a lithium nickel manganese cobalt oxide cathode exhibits a stable cycling performance showing limited capacity decay. This approach provides an effective electrolyte manipulation strategy to develop high‐voltage lithium metal batteries.     

Columnar Lithium Metal Anodes

The rechargeable lithium metal anode is of utmost importance for high‐energy‐density batteries. Regulating the deposition/dissolution characteristics of Li metal is critical in both fundamental researches and practical applications. In contrast to gray Li deposits featured with dendritic and mossy morphologies, columnar and uniform Li is herein plated on lithium‐fluoride (LiF)‐protected copper (Cu) current collectors. The electrochemical properties strongly depended on the microscale morphologies of deposited Li, which were further embodied as macroscale colors. The as‐obtained ultrathin and columnar Li anodes contributed to stable cycling in working batteries with a dendrite‐free feature. This work deepens the fundamental understanding of the role of LiF in the nucleation/growth of Li and provides emerging approaches to stabilize rechargeable Li metal anodes.     

Highly Stable Lithium Metal Batteries Enabled by Regulating the Solvation of Lithium Ions in Nonaqueous Electrolytes

Safe and rechargeable lithium metal batteries have been difficult to achieve because of the formation of lithium dendrites. Herein an emerging electrolyte based on a simple solvation strategy is proposed for highly stable lithium metal anodes in both coin and pouch cells. Fluoroethylene carbonate (FEC) and lithium nitrate (LiNO₃) were concurrently introduced into an electrolyte, thus altering the solvation sheath of lithium ions, and forming a uniform solid electrolyte interphase (SEI), with an abundance of LiF and LiN_xO_y on a working lithium metal anode with dendrite‐free lithium deposition. Ultrahigh Coulombic efficiency (99.96 %) and long lifespans (1000 cycles) were achieved when the FEC/LiNO₃ electrolyte was applied in working batteries. The solvation chemistry of electrolyte was further explored by molecular dynamics simulations and first‐principles calculations. This work provides insight into understanding the critical role of the solvation of lithium ions in forming the SEI and delivering an effective route to optimize electrolytes for safe lithium metal batteries.     

Nanomaterials for rechargeable lithium batteries

Energy storage is more important today than at any time in human history. Future generations of rechargeable lithium batteries are required to power portable electronic devices (cellphones, laptop computers etc.), store electricity from renewable sources, and as a vital component in new hybrid electric vehicles. To achieve the increase in energy and power density essential to meet the future challenges of energy storage, new materials chemistry, and especially new nanomaterials chemistry, is essential. We must find ways of synthesizing new nanomaterials with new properties or combinations of properties, for use as electrodes and electrolytes in lithium batteries. Herein we review some of the recent scientific advances in nanomaterials, and especially in nanostructured materials, for rechargeable lithium-ion batteries.     

Electrolyte Regulation towards Stable Lithium‐Metal Anodes in Lithium–Sulfur Batteries with Sulfurized Polyacrylonitrile Cathodes

Lithium–sulfur (Li–S) batteries are highly regarded as the next‐generation energy‐storage devices because of their ultrahigh theoretical energy density of 2600 Wh kg^?1. Sulfurized polyacrylonitrile (SPAN) is considered a promising sulfur cathode to substitute carbon/sulfur (C/S) composites to afford higher Coulombic efficiency, improved cycling stability, and potential high‐energy‐density Li–SPAN batteries. However, the instability of the Li‐metal anode threatens the performances of Li–SPAN batteries bringing limited lifespan and safety hazards. Li‐metal can react with most kinds of electrolyte to generate a protective solid electrolyte interphase (SEI), electrolyte regulation is a widely accepted strategy to protect Li‐metal anodes in rechargeable batteries. Herein, the basic principles and current challenges of Li–SPAN batteries are addressed. Recent advances on electrolyte regulation towards stable Li‐metal anodes in Li–SPAN batteries are summarized to suggest design strategies of solvents, lithium salts, additives, and gel electrolyte. Finally, prospects for future electrolyte design and Li anode protection in Li–SPAN batteries are discussed.     

Lithium-ion conducting electrolyte salts for lithium batteries

This paper presents an overview of the various types of lithium salts used to conduct Li(+) ions in electrolyte solutions for lithium rechargeable batteries. More emphasis is paid towards lithium salts and their ionic conductivity in conventional solutions, solid-electrolyte interface (SEI) formation towards carbonaceous anodes and the effect of anions on the aluminium current collector. The physicochemical and functional parameters relevant to electrochemical properties, that is, electrochemical stabilities, are also presented. The new types of lithium salts, such as the bis(oxalato)borate (LiBOB), oxalyldifluoroborate (LiODFB) and fluoroalkylphosphate (LiFAP), are described in detail with their appropriate synthesis procedures, possible decomposition mechanism for SEI formation and prospect of using them in future generation lithium-ion batteries. Finally, the state-of-the-art of the system is given and some interesting strategies for the future developments are illustrated.     

二甲基亚砜在锂二次电池中的应用

采用二甲基亚砜(DMSO)作为锂二次电池的电解液, 研究了锂在DMSO中的沉积形貌和循环效率. 比较了六氟磷酸锂(LiPF₆)在DMSO、 碳酸丙烯酯(PC)和1,3-二氧环戊烷(DOL)3种溶剂中的沉积形貌和循环效率, 并研究了LiPF₆、 四氟硼酸锂(LiBF₄)、 高氯酸锂(LiClO₄)和二(三氟甲基磺酰)亚胺锂(LiTFSI)4种锂盐在DMSO中的沉积形貌和循环效率. 结果表明, 锂在DMSO中沉积得到的表面光滑平整且致密均匀, 循环效率在前10周要高于在PC中的, 溶剂DMSO有望用于金属锂二次电池中.     

动力锂离子电池正极材料磷酸钒锂制备方法

锂离子电池新型正极材料的开发是当前的研究热点,其中磷酸盐材料以其结构稳定、安全性能好及资源丰富等优点备受关注。磷酸钒锂理论能量密度可达500mWh/g,具有较高的电子离子导电性、理论充放电容量及充放电电压平台,被认为是一种极具竞争优势和应用前景的动力锂离子电池正极材料。传统磷酸钒锂合成方法有固相合成法、碳热还原法、溶胶凝胶法和水热合成法等,近年来,又出现了湿法固相配位法、微波固相合成法和流变相法等新型合成方法。本文简要介绍了磷酸钒锂的结构和性能特点,对磷酸钒锂制备方法的最新研究进展进行了较为全面的阐述,并详细介绍了本研究团队近年来在磷酸钒锂材料新型合成方法方面的探索成果。同时对各种合成方法的制备工艺及材料性能进行了对比分析,并探讨了当前存在的问题及未来的研究方向。     

柱状金属锂沉积物:电解液添加剂的影响

二次电池的能量密度已成为推动电动汽车和便携式电子产品技术向前发展的重要指标。使用石墨负极的锂离子电池正接近其理论能量密度的天花板,但仍难以满足高端储能设备的需求。金属锂负极因其极高的理论比容量和极低的电极电位,受到了广泛关注。然而,锂沉积过程中枝晶的生长会导致电池安全性差等问题。电解液对金属锂的沉积有着至关重要的影响。本文设计了一种独特的电解槽体系来进行柱状锂的沉积,研究了不同电解液体系(1mol·L^-1LiPF6-碳酸乙烯酯/碳酸二乙酯(EC/DEC,体积比为1:1)、1 mol·L^-1 LiPF6-氟代碳酸乙烯酯(FEC,体积分数5%)-EC/DEC (体积比为1:1))对金属锂沉积的影响。对两种电解液中金属锂沉积物长径比的研究表明,电解液的组分可以显著地影响金属锂的沉积形貌,在加入氟代碳酸乙烯酯(FEC)添加剂之后,柱状锂的直径从0.3–0.6μm增加到0.7–1.3μm,长径比从12.5下降到5.6。长径比的降低有助于减小金属锂和电解液的反应面积,提高金属锂负极的利用率和循环寿命。通过考察循环后锂片的表面化学性质,发现FEC的分解增加了锂表面固态电解质界面层中氟化锂(LiF)组分的比例,提高了界面层中锂离子的扩散速率,减少了锂的成核位点,从而给予锂核更大的生长空间,降低了沉积出的柱状锂的长径比。