锂离子电池负极材料多孔Li4Ti5O12/C的制备与表征

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高剑, 穆鑫, 李建军, 何向明, 姜长印. 锂离子电池负极材料多孔Li₄Ti₅O₁₂/C的制备与表征 . 无机材料学报, 2012, 27(3): 253-257
GAO Jian, MU Xin, LI Jian-Jun, HE Xiang-Ming, JIANG Chang-Yin. Preparation and Characterization of Porous Spherical Li₄Ti₅O₁₂/C Anode Material for Lithium Ion Batteries . Journal of Inorganic Materials, 2012, 27(3): 253-257 复制到剪切板

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锂离子电池负极材料多孔Li₄Ti₅O₁₂/C的制备与表征

高剑, 穆鑫, 李建军, 何向明, 姜长印

清华大学核能与新能源技术研究院, 北京100084

高剑(1978-), 博士, 助理研究员. E-mail: gaoj@mail.tsinghua.edu.cn

基金:国家自然科学青年基金(20903061); 科技部“973”计划课题(2011CB935902);

摘要

将钛源、锂源和碳源三种化合物一起球磨湿混成均匀浆料, 再依次经过喷雾干燥和高温煅烧制得晶粒表面包覆纳米碳层的多孔球形钛酸锂(Li₄Ti₅O₁₂)材料. 通过XRD、SEM、TEM、BET和电化学性能测试等分析手段表明, 合成出的Li₄Ti₅O₁₂/C材料为纳米一次粒子(晶粒)组成的球形二次粒子(颗粒), 具有较大的比表面积, 达到 39.5 m²/g; 在0.1C、1.0C和5.0C倍率下的首次放电比容量分别达到172.2、168.2和153.6 mAh/g, 并表现出优良的循环性能. 晶粒表面包覆碳的多孔Li₄Ti₅O₁₂材料具有明显的高倍率性能和循环稳定性优势.

关键词: Li₄Ti₅O₁₂; 多孔; 球形结构; 晶粒包碳; 倍率

中图分类号:TQ174 文献标志码:A 文章编号:1000-324X(2012)03-0253-05

Preparation and Characterization of Porous Spherical Li₄Ti₅O₁₂/C Anode Material for Lithium Ion Batteries

GAO Jian, MU Xin, LI Jian-Jun, HE Xiang-Ming, JIANG Chang-Yin

Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China

Fund:National Science Foundation of China (20903061); 973 Program (2011CB935902);

Abstract

Titanium, lithium and carbon source compounds were mixed by ball milling firstly, then the slurry was spray dried to prepare spherical precursor. The porous spherical spinel Li₄Ti₅O₁₂/C powders were synthesized by calcining the precursor. XRD, SEM, TEM, BET testing and determination of the electrochemical properties show that the prepared Li₄Ti₅O₁₂/C powders are in form of spherical particles which is composed of nanocrystals. The specific surface area of Li₄Ti₅O₁₂/C powders is as high as 39.5 m²/g. The initial discharge specific capacities of the Li₄Ti₅O₁₂/C anode reach 172.2, 168.2 and 153.6 mAh/g at 0.1C, 1C and 5.0C rates, respectively. The Li₄Ti₅O₁₂/C anode also exhibits excellent cycle performance. The porous Li₄Ti₅O₁₂ material coated by carbon displays excellent high rate performance and cycling stability.

Keyword: Li₄Ti₅O₁₂; porous; spherical; carbon coating; cycling capacity

Show Figures

锂离子电池已被广泛应用于移动电话、手提电脑和摄像机等便携式电子产品电源, 并作为动力电池和储能电源逐渐应用于混合动力车、纯电动车和可再生能源电站. 动力电源对电极材料的要求非常高, 除需要具有高比能量和高比功率外, 成本、安全性及循环性能也需要满足要求. 目前已经商品化的锂离子电池负极材料主要是石墨化碳材料, 但作为动力型锂离子电池负极存在安全性较差的问题. 尖晶石型钛酸锂(Li₄Ti₅O₁₂)以其出色的安全特性和长循环寿命成为极具有商业化前景的动力型锂离子电池负极材料^{[ 1, 2]}.

Li₄Ti₅O₁₂材料在常温下锂离子的化学扩散系数为 2×10^-8cm²/s, 比碳负极大一个数量级, 但是其固有电导率较低(仅为10^-9S/cm), 这主要是因为其电子导电率只有10^-13S/cm. 如此低的电子电导率在高倍率充放电时, 容易产生较大极化且比容量衰减很快, 从而影响电化学性能的发挥^{[ 3]}. 为了提高Li₄Ti₅O₁₂电极材料的电子电导率, 研究人员做了诸多改性尝试, 如碳包覆^{[ 4, 5, 6]}、引入其它导电介质、元素掺杂、制备纳米颗粒^{[ 7, 8]}和其它工艺改进^{[ 9, 10, 11]}等等. 碳包覆和制备纳米颗粒是改善Li₄Ti₅O₁₂材料大电流性能的两种很好的措施, 但是只采取一种措施存在不足: 单分散的纳米颗粒密度低、电极制作困难、需多加导电剂造成能量密度降低等; 碳包覆时碳源化合物的选择也非常重要.

Li₄Ti₅O₁₂的制备方法很多, 包括高温固相合成法^{[ 12, 13]}、溶胶-凝胶法^{[ 14]}、水热离子交换法^{[ 15]}和高能球磨法^{[ 16]}等. 本工作主要采用喷雾干燥和高温固相法结合, 以纳米级核/壳结构的聚丙烯酸酯类共聚物作为包覆碳源, 制备纳米碳层包覆的中空多孔Li₄Ti₅O₁₂负极材料, 使材料的倍率性能和循环比容量得到大幅度提高.

1 实验

1.1 多孔Li₄Ti₅O₁₂/C的合成

采用锐钛矿型Nano-TiO₂(杭州万景新材料有限公司; 粒径: 20~40 nm)和Li₂CO₃(四川省射洪锂业有限责任公司; 99.9%, 纯度≥99.9%)分别作钛源和锂源, 纳米级核/壳结构的聚丙烯酸酯类共聚物2602(武汉安泰化学工业有限公司)用作碳源. 按化学计量比5:4分别称取钛源和锂源, 再称取按钛源摩尔量计算得出的Li₄Ti₅O₁₂质量20wt%的碳源, 加入适量去离子水一起球磨(500 r/min, 3 h), 制得均匀浆料后, 再进行喷雾干燥(进口温度: 160℃, 出口温度: 80~90℃; 压力: 0.1~0.2 MPa; 进料速度: 5 mL/min)制备球形粉末前驱体, 然后在N₂气氛管式炉中900℃煅烧16 h, 然后随炉自然降温至室温, 制得碳包覆的中空多孔球形Li₄Ti₅O₁₂粉末, 用LTO/C表示, 其中碳含量为1.1wt%. 另外用相同的方法制备不含碳的电极材料用作空白对比试验, 用LTO表示.

1.2 实验半电池的组装

把电极材料LTO/C粉末、导电剂乙炔黑和粘结剂聚四氟乙烯 (PTFE)按质量比为 8: 1: 1的比例均匀混合, 用压片机压制成厚度约为0.6 mm的薄片, 再用冲子裁成φ6 mm的圆片, 放入 120℃的真空干燥箱内干燥24 h备用. 本实验主要制作2032纽扣电池进行半电池测试, 以制作的电极片为电池正极, 金属锂片(天津中能锂业有限公司)为负极, 隔膜用 Celgard2400微孔聚丙烯膜, 电解液为1 mol/L LiPF₆的EC+DMC(体积比1:1)(张家港国泰华荣化工新材料有限公司)溶液, 在充满干燥氩气(水分含量<0.1×10^-6, 氧含量<5×10^-6)的手套箱内组装成实验电池.

1.3 性能测试

根据TG-DSC(STA409PC, 德国耐驰NETZSCH)对烧结制度进行设计; 用 Rigaku D/max-2500PC X射线衍射仪(Cu靶, λ=0.154056 nm; 管压40 kV, 电流200 mA; 扫描范围及速度2 θ=10°~80°, 3°/min)对Li₄Ti₅O₁₂粉末进行相分析; 用扫描电子显微镜(Sirion200; 分辨率1 nm, 电压10 kV)观察样品的微观形貌; 用场发射透射电子显微镜(Tecnai G2F20 S-Twin TEM; 点分辨率0.24 nm, 放大倍数25~100万倍)观察碳包覆; 用激光粒度分析仪(欧美克LS-POP(Ⅵ) ; 粒径测量范围: 0.2~500 μm)测试颗粒粒径; 用BET法测试材料的比表面积和孔径分布; 用 LAND电池测试系统(武汉金诺电子有限公司)对实验电池进行恒流和倍率充放电循环测试, 充放电截止电压为1~3 V.

2 结果与讨论

2.1 TG-DSC分析

喷雾干燥所得前驱体的TG-DSC曲线如图1所示, 可以看出, 随着温度的升高, 在DSC曲线上出现1、2、3和4四个吸热峰和一个放热峰5, 同时在热重曲线上表现出对应的失重台阶. DSC曲线上100~320℃温度范围内的一个宽大吸热峰1主要是材料表面吸附水和颗粒空隙内吸附水的脱除; 360~ 400℃范围内两个尖锐的吸热峰2和3, 分别对应于有机碳源化合物受热分解和Li₂CO₃的分解; 457℃处的吸热峰4, 对应于如下反应: 5TiO₂+2Li₂CO₃→ Li₄Ti₅O₁₂+2CO₂; 在500~800℃之间失重趋缓, 并伴随有持续缓慢的放热, 这是Li₄Ti₅O₁₂生成反应逐渐完成的过程; 850℃左右再出现一个比较明显的放热峰5, 可以看作是Li₄Ti₅O₁₂反应完全并晶化; 850℃以后TG曲线变得平直, 样品达到一个比较稳定的状态. 以上结果表明, 有机碳源化合物在400℃左右裂解碳化, 稳定的Li₄Ti₅O₁₂晶体主要是在850℃左右生成的, 因此, 选定烧结工艺为: 升温至400℃并保温2 h, 然后再分别升温至750、800、850和900℃并保温16 h.

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	图1 喷雾干燥制得前驱体的TG-DSC 曲线Fig. 1 TG-DSC curves of precursor powders by spray drying

2.2 X射线衍射分析(XRD)

从图2可知, 当烧结温度在700~800℃之间时, 所得产物含有大量TiO₂和Li₂TiO₃等杂质. 热处理温度在850℃时杂相明显减少. 当烧结温度为900℃时, 产物XRD图谱与PDF49-0207标准卡片对照, 产物为纯相Li₄Ti₅O₁₂. 有机碳源化合物热处理生成的裂解碳没有出现衍射峰, 说明生成的碳为无定型态. 另外, 实验中还考察了热处理时间对反应的影响(图略), 900℃时对前驱体分别热处理5、10和20 h, 5和10 h的产物杂相较多; 而热处理20 h产物的衍射谱图与热处理16 h的基本一致, 说明反应在16 h时已完成, 延长热处理时间不会使晶相再发生变化. 由此可见, 900℃热处理16 h即获得目标产物Li₄Ti₅O₁₂.

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	图2 前驱体经不同温度烧结产物的XRD图谱Fig. 2 XRD patterns of Li₄Ti₅O₁₂powders sintered at different temperatures

2.3 形貌分析

采用喷雾干燥法制备的球形颗粒前驱体、900℃烧结后的球形LTO/C颗粒、LTO颗粒和LTO/C颗粒表面的扫描电镜图及晶粒表面的透射电镜图如图3所示. 从图3(a)可知前驱体粉末为表面光滑的球形颗粒, 颗粒平均粒径在15 μm左右. 经过900℃热处理后颗粒仍然保持球形形貌, 但是颗粒收缩较大, 平均粒径降为5 μm左右, 球形颗粒经烧结后表面分布众多孔洞, 平均孔径为 3.421 nm, 这主要是水性高分子碳源高温裂解碳化留下的, 如图3(b)所示, LTO/C的比表面积为 39.5 m²/g. 而作为对比的LTO样品晶粒明显长得更大, 其比表面积只有6.1 m²/g, 如图3(e) 所示. 由于裂解碳的表面包覆和孔洞的存在, 抑制了晶粒的进一步融合生长, 由图3(c)可知, 晶粒形貌为板状, 平均粒径为150 nm左右. 在电极材料与电解液接触时, 由于材料比表面积的提高使得固液接触面积也得到提高, 这样就缩短了锂离子在晶体中的扩散路程和电子传输路径, 有利于减少电极材料在充放电循环过程中的极化现象, 更适用于高倍率充放电.

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	图3 前驱体及热处理后样品的电镜照片Fig. 3 SEM and TEM images of precursor and Li₄Ti₅O₁₂ powders after sintered at 900℃(a) Precursor powder; (b) Li₄Ti₅O₁₂/C powders; (c) Li₄Ti₅O₁₂/C crystals; (d) Surface of crystals; (e) Li₄Ti₅O₁₂ powders

从图3(d)可以看出, 一层厚度约为5 nm的无定型碳层较为均匀地包覆在了Li₄Ti₅O₁₂晶体表面, 晶粒之间也是通过碳进行连接的, 说明在颗粒内部已经形成了较好的导电网络, 这对提高材料的电导率非常有利.

2.4 恒流充放电测试

LTO/C和LTO样品在不同倍率下的首次充放电曲线如图4所示. 可见, LTO/C样品以0.1 C倍率进行充放电测试时放电比容量高达172.2 mAh/g, 接近于理论比容量. 当以1 C倍率进行充放电测试时, 放电比容量达167.8 mAh/g, 与0.1 C倍率的比容量相比, 保持率为97.4%. 当以1 C倍率充电5 C倍率放电时, 放电比容量为153.6 mAh/g, 保持率为89.2%. 而LTO样品在0.1 C和1.0 C倍率下的首次放电比容量仅为160和114.8 mAh/g, 两者的差距很明显. 通过晶粒表面碳包覆改性后电极材料的电化学性能有了很大提高, 这是晶粒粒径变小、晶粒表面碳包覆、多孔结构等多种因素共同作用的结果.

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	图4 LTO/C和LTO样品在不同倍率下的首次充放电曲线Fig. 4 First charge-discharge curves of LTO/C and LTO samples at different rates

图5为LTO/C和LTO样品在不同倍率下的循环性能曲线. LTO/C样品在0.1 C、1.0 C和5.0 C倍率下的稳定循环放电比容量分别为170、165和 145 mAh/g; 而LTO样品在0.1 C倍率下的稳定循环放电比容量只有160 mAh/g, 并且在1.0 C倍率下放电比容量衰减非常明显, 20次循环后放电比容量仅有89.9 mAh/g.

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	图5 LTO/C 和LTO样品在不同充放电倍率下的循环性能曲线Fig. 5 Specific discharge capacity dependence on cycle number of LTO/C and LTO samples at different rates

3 结论

采用喷雾干燥和高温固相法制备了中空多孔球形Li₄Ti₅O₁₂/C负极材料. 选择聚丙烯酸酯类共聚物作为碳源, 通过高温裂解碳化使其均匀地包覆在晶粒表面, 既形成了多孔的球形结构, 又具备了较好的导电网络, 从而显著改善了Li₄Ti₅O₁₂材料的电化学性能, 特别是倍率性能和循环性能. 0.1 C倍率下, Li₄Ti₅O₁₂/C负极材料的首次放电比容量高达 172.2 mAh/g, 接近于理论比容量; 1.0 C倍率下循环20次后放电比容量仍有167.0 mAh/g, 容量保持率为99.5%; 5.0 C倍率下循环20次后放电比容量为147.2 mAh/g, 容量保持率达95.8%.

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[14]	Ju Seo Hee, Kang Yun Chan. Effects of types of drying control chemical additives on the morphologies and electrochemical properties of Li₄Ti₅O₁₂ anode powders prepared by spray pyrolysis. J. Alloys and Compounds, 2010, 506(2): 913-916. [本文引用:1] [JCR: 2.39]
[15]	Li Junrong, Tang Zilong, Zhang Zhongtai. Controllable formation and electrochemical properties of one-dimensional nanostructured spinel Li₄Ti₅O₁₂. Electrochem. Commun. , 2005, 7: 894-899. [本文引用:1] [JCR: 4.425]
[16]	潘晓燕. 机械驱动下纳米二氧化钛的结构与相变. 上海: 上海大学博士论文, 2004. [本文引用:1]

2005

0.531

1.106

. 2005, 20(3):537-544

Progress in research on Li₄Ti₅O₁₂ as anode for electrochemical devices

Chengdu Institute of Organic Chemistry; the Chinese Academy of Sciences; Chengdu 610041; China

The recent progress in research concerning spinel Li₄Ti₅O₁₂ as anode for energy storage devices was reviewed. Physical and electrochemical properties of Li₄Ti₅O₁₂ were introduced. The emphasis was laid on the electrochemical performance of Li₄Ti₅O₁₂ as anode in hybrid supercapacitors. Information regarding the synthetic methods for the preparation of Li₄Ti₅O₁₂ and recent improving work were thoroughly presented.

介绍了负极材料Li₄Ti₅O₁₂的物理特性和电化学性能,详细介绍并评述了Li₄Ti₅O₁₂ 在锂离子电池和不对称型超级电容器中的应用情况,总结了Li₄Ti₅O₁₂的不同合成方法及材料的电化学改性研究进展.

... 尖晶石型钛酸锂(Li₄Ti₅O₁₂)以其出色的安全特性和长循环寿命成为极具有商业化前景的动力型锂离子电池负极材料^[1,2] ...

2010

4.675

0.0

... 尖晶石型钛酸锂(Li₄Ti₅O₁₂)以其出色的安全特性和长循环寿命成为极具有商业化前景的动力型锂离子电池负极材料^[1,2] ...

2010

2.046

0.0

... 如此低的电子电导率在高倍率充放电时, 容易产生较大极化且比容量衰减很快, 从而影响电化学性能的发挥^[3] ...

2004

4.675

0.0

... 为了提高Li₄Ti₅O₁₂电极材料的电子电导率, 研究人员做了诸多改性尝试, 如碳包覆^[4,5,6]、引入其它导电介质、元素掺杂、制备纳米颗粒^[7,8]和其它工艺改进^[9,10,11]等等 ...

2009

0.531

1.106

. 2009, 24(1):139-142 DOI:10.3724/SP.J.1077.2009.00139

Preparation of spherical nanocrystal LiFePO₄ and Li₄Ti₅O₁₂ and investigation of the LiFePO₄/Li₄Ti₅O₁₂ cell

Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 102201, China

The spherical nanocrystal LiFePO₄/C and Li₄Ti₅O₁₂/C are synthesized via “controlled crystallization” and “outer gel” technics, respectively. XRD, SEM, BET testing and the determination of the electrochemical properties show that the LiFePO₄/C and Li₄Ti₅O₁₂/C particles are spherical nanocrystals. The products exhibit great specific surface area. The tap-densities of spherical LiFePO₄/C and Li₄Ti₅O₁₂/C powders are as high as 1.25 and 1.71g/cm³, respectively. The initial discharge specific capacities of the LiFePO₄/C and Li₄Ti₅O₁₂/C reach 144.0 and 144.2mAh/g at 1C rate. The materials also exhibit excellent cycle performance. A 1.8 V lithium-ion battery composed of LiFePO₄/C and Li₄Ti₅O₁₂/C shows a quite flat operating voltage of 1.8V with excellent cycleability.

分别通过“控制结晶”和“外凝胶”工艺合成了球形纳米晶LiFePO₄/C和Li₄ Ti₅O₁₂/C材料.通过XRD、SEM、比表面及电化学性能测试等分析手段表明，合成的LiFePO₄/C和Li₄Ti₅O₁₂/C材料均为纳米一次粒子（晶粒）组成的球形二次粒子（颗粒），具有较大的比表面积，振实密度分别达到1.25和1.71g/cm³；1C倍率下的首次放电比容量分别达到144.0和144.2mAh/g，并表现出优良的循环性能.以LiFePO₄/C和Li₄Ti₅O₁₂/C为正负极材料组成的1.8V锂离子电池具有平稳的充放电电压平台和优异的循环性能.

2010

2.046

0.0

2006

8.238

0.0

2008

3.777

0.0

. 2008, 53(24):7242-7247 DOI:10.1016/j.electacta.2008.05.002

Microstructure effect on the electrochemical property of Li₄Ti₅O₁₂ as an anode material for lithium-ion batteries

Abstract

Porous (P-) and dense (D-) lithium titanate (Li₄Ti₅O₁₂) powders as an anode material for lithium-ion batteries have been synthesized by spray drying followed by solid-state calcination. Electrochemical testing results showed that the discharge capacities of P-Li₄Ti₅O₁₂ are 144 mAh/g, 128 mAh/g and 73 mAh/g at the discharging rate of 2C, 5C and 20C, respectively (cut-off voltages: 0.5–2.5 V). The corresponding values for D-Li₄Ti₅O₁₂ are 108 mAh/g, 25 mAh/g and 17 mAh/g. The higher capacity of the P-Li₄Ti₅O₁₂ at high charge/discharge rates was attributed to the shorter transport path of Li ions and higher electronic conductivity in the P-Li₄Ti₅O₁₂ as a result of its smaller primary particle size and higher surface area compared with those of the D-Li₄Ti₅O₁₂.

2007

0.531

1.106

. 2007, 22(5):879-884 DOI:10.3724/SP.J.1077.2007.00879

Preparation and key influencing factors of Li₄Ti₅O₁₂ as electrode material

1. Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China; 2. Jinzhou Kaimei Power Co. Ltd., Jinzhou 121000, China; 3. Beijing Key Lab of Advanced Energy Material and Technology, Beijing 100083, China

Effects of sintering temperature, time and the lithium salts on the properties of Li₄Ti₅O₁₂ synthesized by a solid-state-method were studied based on orthogonal experiments. The results show that sintering temperature is the most principal factor on the performance of Li₄Ti₅O₁₂. Synthesized at proper sintering temperature with appropriate time, the product will have good electrochemical properties with finer particle size and better crystallinity. The high-rate discharge/charge property of Li₄Ti₅O₁₂ prepared with LiNO₃ is much better. Li₄Ti₅O₁₂ obgained at the optimum condition, namely preparing with LiNO₃ and sintering at 800℃ for 12h, performs well when charged and discharged with high current density. It delivers discharge capacities of 151mAh·g^-1, 140mAh·g^-1 and 115mAh·g^-1 at the rate of 1C, 2C and 5C, respectively, and shows good reversibility.

在正交试验的基础上考察了烧结温度及时间、锂源对固相合成Li₄Ti₅O₁₂性能的影响. 结果表明, 烧结温度为最显著影响因素; 恰当的温度与时间组合可以制备粒径小、结晶度好的产物, 具有良好的电化学性能; 硝酸锂为锂源制备的Li₄Ti₅O₁₂具有较好的高倍率充放电能力. 以LiNO₃为锂源, 空气气氛下800℃烧结12h, 所得Li₄Ti₅O₁₂在大电流密度下充放电性能良好, 1C、2C、5C时的放电容量分别达到了151、140、115mAh·g^-1, 且具有良好的可逆性.

2009

0.0

2004

0.0

2005

4.675

0.0

... Li₄Ti₅O₁₂的制备方法很多, 包括高温固相合成法^[12,13]、溶胶-凝胶法^[14]、水热离子交换法^[15]和高能球磨法^[16]等 ...

2006

0.0

... Li₄Ti₅O₁₂的制备方法很多, 包括高温固相合成法^[12,13]、溶胶-凝胶法^[14]、水热离子交换法^[15]和高能球磨法^[16]等 ...

2010

2.39

0.0

... Li₄Ti₅O₁₂的制备方法很多, 包括高温固相合成法^[12,13]、溶胶-凝胶法^[14]、水热离子交换法^[15]和高能球磨法^[16]等 ...

2005

4.425

0.0

. 2005, 7:894-899 DOI:10.1016/j.elecom.2005.06.012

Controllable formation and electrochemical properties of one-dimensional nanostructured spinel Li₄Ti₅O₁₂

Abstract

Novel spinel Li₄Ti₅O₁₂ with nanotubes/nanowires morphology and high surface area has been prepared by a low temperature hydrothermal lithium ion exchange processing from hydrogen titanate nanotubes/nanowires precursors. The shape and morphology of spinel Li₄Ti₅O₁₂ are controllable by varying the hydrogen titanate precursors (nanotube, nanowire, nanorod and nanobelt) from alkaline-hydrothermal approach. The crystal structure and morphology of the as-prepared lithium titanate nanotubes/nanowires have been investigated by TEM, HRTEM and XRD, respectively. The formation temperature of spinel Li₄Ti₅O₁₂ nanotubes/nanowires is lower than that of bulk materials counterpart prepared by solid-state reaction or by sol–gel processing. The well reversible cyclic voltammetric results of both electrodes indicate enhanced electrochemical kinetics for lithium insertion. These novel one-dimensional nanostructured materials may find promising applications in lithium ion batteries and electrochemical cells.

... Li₄Ti₅O₁₂的制备方法很多, 包括高温固相合成法^[12,13]、溶胶-凝胶法^[14]、水热离子交换法^[15]和高能球磨法^[16]等 ...

2004

0.0

... Li₄Ti₅O₁₂的制备方法很多, 包括高温固相合成法^[12,13]、溶胶-凝胶法^[14]、水热离子交换法^[15]和高能球磨法^[16]等 ...