Study of Poly-Anion Cathode Materials for Lihium Ion Batteries

聚阴离子型正极材料是当前锂离子电池新一代正极材料的研究热点之一。聚阴离子型正极材料（如磷酸盐系列正极材料）通常具有价格低廉、电化学循环稳定性及热稳定性好等优点，但其电子电导率低的特点制约其在高功率型电极材料方面的应用。本文首先用原位包覆碳的方法合成出LiFePO4/C复合正极材料，并通过优化其合成条件使其电化学性能得到了很大提高。尽管对聚阴离子型正极材料可以采取包碳、掺杂等方法来改善其性能，但能否通过改善电极材料的微观结构（如引入介孔结构）来改善其电化学性能，并探讨其可能的作用机理，这显然是一个相当有趣的课题。本文对介孔型聚阴离子型正极材料进行探索性研究，把介孔结构引入FePO4、TiP2O7...Nowadays, poly-anion compounds are one of the extensively studied cathode materials for the anticipated next generation lithium ion batteries. Poly-anion cathode materials (such as phosphate cathode materials) are attractive for low-cost, good cyclic stability, and excellent thermal stability. However, their low electronic conductivity impedes their use as electrode materials in high-power batteri...学位：理学博士院系专业：化学化工学院化学系_物理化学(含化学物理)学号：B20022503

Progress in Polyanion-Type Cathode Materials for Lithium Ion Batteries

综述了各种聚阴离子型锂离子电池正极材料的研究现状,重点对各种材料的结构和性能的关系,尤其是聚阴离子在正极材料中的作用,以及改善材料电导率的各种方法及其机理进行了总结和探讨。Recent progress on the polyanion-type cathode materials for lithium ion batteries is reviewed. Emphasis is placed on the discussion of the relationships between structures and properties of the cathode materials, especially on the role of the polyanion and how to improve their low electronic conductivity.国家自然科学基金资助课题(No.29925310

Preparation and performance of titanium phosphate with different mesoporous structure

采用溶胶凝胶模板法结合煅烧的方法,通过选用不同的模板剂合成得到具有不同介孔结构的磷酸钛材料,运用X-射线粉末晶体衍射技术(Xrd)、低温n2吸脱附技术和高分辨透射电子显微技术(HrTEM)对样品进行了表征,并分别对各材料的介孔结构及其电化学性能进行了研究。结果表明,材料介孔结构的长程有序性及其孔径大小都对材料的电化学性能有影响,例如在大电流密度下(如:150MA/g),长程有序性较好的与长程有序性较差的磷酸钛介孔材料的首次放电比容量分别为93.9、67.9MA/g,经过100次循环后,容量的保持率分别为54%、20%;大孔径与小孔径的磷酸钛介孔材料的首次放电比容量分别为96.1、67.9MA/g,经过50次循环后,容量的保持率分别为66%、17%。Titanium phosphate materials with different mesoporous structure were prepared by sol-gel different templates combined with calcination method.The mesoporous structure of the materials was characterized by small angle X-ray diffraction (SA-XRD) method, N2 adsorption/desorption techniques, and high resolution transmission electron microscopy (HRTEM).The results show that both the length of ordered mesostructure and pore size has a great influence on the electrochemical performance of the titanium phosphate materials.For example, the titanium phosphate materials with ordered and worse structure respectively delivers an initial discharge capacity of about 93.9 mA/g and 67.9 mA/g at 150 mA/g, and after 100 cycles, the capacity retention is 54% and 20% respectively.However, the titanium phosphate materials with the large and small pore size respectively delivers the initial discharge capacity of about 96.1 mA/g and 67.9 mA/g, and after 50 cycles, the capacity retention was 66% and 17% respectively.国家自然科学基金纳米科技重大计划课题资助(90606015);湖南省自然科学基金项目(09JJ3028);湖南省重点学科建设项目(2006-180

Progress in polyanion-type cathode materials for lithium ion batteries

Recent progress on the polyanion-type cathode materials for lithium ion batteries is reviewed. Emphasis is placed on the discussion of the relationships between structures and properties of the cathode materials, especially on the role of the polyanion and how to improve their low electronic conductivity

Lithium Storage Performance of Hard Carbons Anode Materials Prepared by Different Precursors

以聚丙烯腈、石油沥青和花生壳为前驱体,在1200℃下碳化制备三种不同的硬碳材料。通过扫描电子显微、X射线衍射、氮气吸附/脱附测试和拉曼光谱等方法探究不同前驱体所制备的硬碳材料的表面形貌和物相结构。通过恒流充放电测试考察了这三种硬碳负极材料的电化学性能。结果表明,花生壳基硬碳的初始放电比容量最高,但首圈库仑效率最低,石油沥青基硬碳的首圈库仑效率最高但是比容量最低,聚丙烯腈基硬碳具有较高的循环比容量和稳定性。Hard carbon is one of the most promising anode material for lithium ion batteries (LIBs) owing to its high stability, widespread availability, low-cost, and excellent performance. The electrochemical properties of hard carbon materials depend strongly on the type of precursors. It is, therefore, very important to choose an excellent hard carbon precursor. Polyacrylonitrile, petroleum pitch and peanut shells were used as raw materials to prepare different hard carbon anode materials for LIBs. These hard carbon anode materials were successfully synthesized in two steps. The selected precursor was firstly carbonized at 600℃ for 1 h in argon atmosphere using heating rate of 1℃·min-1, and then was further carbonized at 1200℃ for 1h in argon atmosphere using heating rate of 5℃·min-1. Under such a low heating rate, a relatively small specific surface area could be obtained as much as possible for the hard carbon anode material. The surface morphology and phase structure of as synthesized hard carbon materials were analyzed by scanning electron microscopy, X-ray diffractometer, nitrogen adsorption analyzer and Raman spectrometer. The ion carrier storage mechanism was further investigated using cyclic voltammetry by examining whether the ion insertion/extraction mechanism is surface-controlled pseudocapacitance or diffusion-limited intercalation. It was further verified that the lithium storage mechanism of hard carbon anode materials is in line with the “adsorption-intercalation” mechanism. The results indicated that polyacrylonitrile-derived hard carbon anode material had low impedance by EIS test. This may be the reason why the low voltage platform of polyacrylonitrile-derived hard carbon materials had a higher specific capacity. The electrochemical performance of different hard carbon materials were investigated through galvanostatic charge and discharge tests. The peanut shell-derived hard carbon material showed the highest initial specific capacity (579.1 mAh·g-1), but the lowest initial coulombic efficiency (49.35%). The petroleum pitch-derived one delivered the highest initial coulombic efficiency (85.97%), but the lowest initial specific capacity (301.7 mAh·g-1). Comparing the cycle performance of these three hard carbon materials, polyacrylonitrile-derived hard carbon materials exhibited the excellent cycling performance (87.17% of capacity over 500 cycles). This study would provide useful assistance to understand the precursor-derived electrochemical properties of hard carbon anode material in practical applications.国家自然科学基金面上项目(21673051);广东省科技厅国际合作项目资助(2019A050510043);广东省科技厅产学研重大专项(2017B010119003)通讯作者:施志聪E-mail:[email protected]:Zhi-CongShiE-mail:[email protected]广东工业大学材料与能源学院,新能源材料与器件系,广东 广州 510000Department of New Energy Materials and Devices, School of Materials and Energy, Guangdong University of Technology, Guangzhou 510000, Guangdong, Chin

Recent Advances in Fluorophosphate and Orthosilicate Cathode Materials for Lithium Ion Batteries

Corresponding authors.SHI Zhi-Cong, Email: [email protected]; Tel: +86-411-39893938. YANG Yong, Email: [email protected]; Tel: +86-592-2185753.[中文文摘]综述了用于锂离子电池的氟磷酸盐和正硅酸盐正极材料的研究现状,重点对各种材料的结构及合成方法与性能的关系,特别是对如何改善材料的电化学性能进行了总结和探讨.展望了这两类锂离子电池正极材料的发展趋势.[英文文摘]We review recent research on fluorophosphate and orthosilicate cathode materials for lithium ion batteries.Emphasis is placed on the relationship between structures,methods of preparation and properties of the cathode materials.We especially focus on factors leading to an improvement in their electrochemical performance.Trends of research into fluorophosphate and orthosilicate cathode materials are also discussed.高等学校博士学科点专项科研基金(20090041120020); 中央高校基本科研业务费专项资金(DUT10JN06)资助项

The Electrochemical Performance Studies on Novel LiFePO4 Cathode Materials for Liion Batteries

通讯联系人, E-mail: yyang@xmu. edu. cn[中文文摘]采用固相反应结合高速球磨法,合成了锂离子电池新型正极材料LiFePO4,并对该材料进行碳包覆处理;采用XRD、SEM、元素分析以及价态化学分析等方法对样品进行表征.实验表明,LiFePO4具有3.4V的放电电压平台,而且包覆碳后的磷酸铁锂具有更好的电化学性能,首次放电容量达147mAh/g,充放电循环100次后容量只衰减9.5%.[英文文摘]The cathode materials of LiFePO4 and LiFePO4 coated with carbon were synthesized by means of solid state reaction and ballmilling. The samples were characterized by X-ray diffraction, scanning electron microscopy, gas-phase element analysis and titration analysis methods. Electrochemical tests of two kinds of materials showed that both of them exhibit a 3. 4V discharge voltage plateau, however , the coated samples demonstr ated the improved performance in terms of discharge capacity and cyclic stability.国家杰出青年基金 (2 992 53 1 0 );国家“973”项目资

The Electrochemical Performance Studies on Novel LiFePO_4 Cathode Materials for Li_ion Batteries

　采用固相反应结合高速球磨法,合成了锂离子电池新型正极材料LiFePO4,并对该材料进行碳包覆处理;采用XRD、SEM、元素分析以及价态化学分析等方法对样品进行表征.实验表明,LiFePO4具有3.4V的放电电压平台,而且包覆碳后的磷酸铁锂具有更好的电化学性能,首次放电容量达147mAh/g,充放电循环100次后容量只衰减9.5%.The cathode materials of LiFePO4 and LiFePO4 coated with carbon were synthesized by means of solid state reaction and ballmilling. The samples were characterized by X_ray diffraction, scanning electron microscopy, gas_phase element analysis and titration analysis methods. Electrochemical tests of two kinds of materials showed that both of them exhibit a 3.4V discharge voltage plateau, however,the coated samples demonstrated the improved performance in terms of discharge capacity and cyclic stability.作者联系地址：厦门大学化学系固体表面物理化学国家重点实验室,厦门大学化学系固体表面物理化学国家重点实验室,厦门大学化学系固体表面物理化学国家重点实验室 福建厦门361005 ,福建厦门361005 ,福建厦门36100

Synthesis of α-MnO_2 Microspheres for the Application in Supercapacitor

利用KMnO4氧化MnCO3微米球前躯体制备MnO2微米球.X射线衍射(XRD)、扫描电子显微镜(SEM)、循环伏安(CV)法等测试表明:该MnO2微米球由弱结晶α-MnO2构成,粒径为0.5~2μm.测试样品的MnO2微米球载量为5 mg.cm-2时,在2 mol.L-1(NH4)2SO4溶液中表现出良好的电容性能:其于2 mV.s-1的扫速下比电容达到了135.6 F.g-1;即使是100 mV.s-1的高扫速,比电容仍保持为118.8 F.g-1.500次循环过程中充放电效率保持在87.8%以上.第500次循环的比电容为110.5 F.g-1.The MnO2 microspheres were prepared through the oxidation of KMnO4 and MnCO3 microspheres precursor.The microstructure and supercapacitor properties of MnO2 were characterized by XRD,SEM and CV.The results show that MnO2 was in a poorly crystalline state with α-crystallographic form,the size of microspheres typically ranged from 0.5 to 2 μm.Loading 5 mg·cm-2 MnO2 microspheres had excellent capacitance behaviors in 2 mol·L-1(NH4)2SO4 solution.The specific capacitance was 135.6 F·g-1 with the scan rate at 2 mV·s-1,and 118.8 F·g-1 with the large scan rate at 100 mV/s.Coulumbic efficiency was still above 87.8% in the 500 cycles,and the specific capacitance of the 500th cycle was 110.5 F·g-1.作者联系地址：大连理工大学化工学院精细化工国家重点实验室;Author's Address: State Key Laboratory of Fine Chemicals,School of Chemical Engineering,Dalian University of Technology,Dalian 116012,Liaoning,Chin

Preparation and Electrochemical Performance of Ordered Mesoporous Titanium Phosphate as Cathode Material for Li-ion Battery

选用合适模板剂由溶胶凝胶法合成高度有序介孔结构的磷酸钛正极材料.研究煅烧温度对材料孔结构及材料的电化学性能的影响,合成样品的结构形貌和比表面分别用XRD、BET、TEM及元素分析仪表征.充放电测试结果表明,该介孔结构正极材料表现出优越的电化学性能,以150 mA/g充放电,首次放电容量高达94 mAh/g,而不含模板剂无孔结构的材料放电容量仅37 mAh/g.Ordered porous titanium phosphate materials were prepared by using the surfactant template combined with the sol-gel method.The samples were characterized by small angle X-ray diffraction(SA-XRD) method,N2 adsorption/desorption techniques,high resolution transmission electron microscopy(HRTEM) and element analysis.It is found that the calcination temperature is a big influence on the porous structure,and electrochemical performance of the titanium phosphate materials.,and the mesoporous titanium phosphate showed good performance in the electrochemical test,the first discharge capacity is 94 mAh/g at the current density of 150 mA/g.On the other hand,the no porous material with a low capacity of 37 mAh/g under the same charge-discharge condition.作者联系地址：厦门大学化学化工学院固体表面物理化学国家重点实验室,厦门大学化学化工学院固体表面物理化学国家重点实验室,厦门大学化学化工学院固体表面物理化学国家重点实验室,厦门大学化学化工学院固体表面物理化学国家重点实验室 福建厦门361005,福建厦门361005,福建厦门361005,福建厦门361005Author's Address: State Key Laboratory for Physical Chemistry of Solid Surfaces,Institute of Chemistry andChemical Engineering,Xiamen University,Xiamen 361005,Fujian,Chin