采用共沉淀高温固相反应法合成锂离子电池正极材料LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2(811),通过掺入Li、Mg和Al元素,并采用SEM、XRD、电化学测试,研究掺杂对材料晶体结构和电化学性能影响规律.实验结果表明:共沉淀过程中三价金属离子(Mn^(...采用共沉淀高温固相反应法合成锂离子电池正极材料LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2(811),通过掺入Li、Mg和Al元素,并采用SEM、XRD、电化学测试,研究掺杂对材料晶体结构和电化学性能影响规律.实验结果表明:共沉淀过程中三价金属离子(Mn^(3+)、Al^(3+))出现会促使少量α-Ni(OH)2形成,而Li^+、Mg^(2+)和Al^(3+)均溶入晶格无杂相析出.高温融锂反应中,三种掺杂元素显著削弱Ni^(2+)出现数量,抑制Ni^(2+)混排进入Li^+格位,大幅提升811基体可逆容量;Mg^(2+)、Al^(3+)掺杂进一步增强基体晶格稳定性,改善其循环性能;Li^+-Al^(3+)共掺杂使之达到最佳:首次充电效率ICE超过90%,0.2C倍率下50次循环容量达195.8 m Ah/g、容量保持率为96.2%.展开更多
LiNi0.78 Co0.2 Al0.02O2 cathode materials were prepared with a novel co-precipitation method followed by heat-treating. The properties of the materials were characterized. XRD patterns showed that no secondary phase a...LiNi0.78 Co0.2 Al0.02O2 cathode materials were prepared with a novel co-precipitation method followed by heat-treating. The properties of the materials were characterized. XRD patterns showed that no secondary phase appeared and the hexagonal lattice parameter c of LiNi0.rsCoo.2AI^0202 was larger than that of LiNi0.8Co0.2O2. The SEM images indicated that the powders of the material were submicron size. The results of the ICP-AES analysis proved that elemental compositions of the material were similar to those of the targeted one. Cyclic voltammetry （3.0- 4. 2 V） illustrated that the new material had good lithium-ion intercalation/de-intercalation performance. The results of galvanostatic cycling showed that the initial specific discharge capacity of the prepared material was 181.4 mAh/g, and the specific discharge capacity was 177.3 mAh/g after 100 cycles （0. 2C, 3.0 - 4. 2 V, vs. Li^＋/Li） with the capacity retention ratio of 97.7%.展开更多
Several lithium-ion batteries of 18650-type were assembled with pristine or Al2O3-coated LiNi0.4Co0.2Mn0.4O2（NCM） as cathode material and mesocarbon microbeads（MCMB） as anode material.The cycling performance of th...Several lithium-ion batteries of 18650-type were assembled with pristine or Al2O3-coated LiNi0.4Co0.2Mn0.4O2（NCM） as cathode material and mesocarbon microbeads（MCMB） as anode material.The cycling performance of the batteries was examined under 25 °C at a 2C rate within a potential range of 2.75―4.20 V.The changes of the crystal structure,the lattice parameter,the mean crystallite size,and the mean micro-strain of pristine NCM and Al2O3-coated NCM during the charge-discharge cycling were determined by X-ray diffraction（XRD）.The results indicate that the bulk structure of Al2O3-coated NCM is more stable than that of pristine NCM,which leads to the better cycling performance of Al2O3-coated NCM compared to that of pristine NCM.展开更多
文摘采用共沉淀高温固相反应法合成锂离子电池正极材料LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2(811),通过掺入Li、Mg和Al元素,并采用SEM、XRD、电化学测试,研究掺杂对材料晶体结构和电化学性能影响规律.实验结果表明:共沉淀过程中三价金属离子(Mn^(3+)、Al^(3+))出现会促使少量α-Ni(OH)2形成,而Li^+、Mg^(2+)和Al^(3+)均溶入晶格无杂相析出.高温融锂反应中,三种掺杂元素显著削弱Ni^(2+)出现数量,抑制Ni^(2+)混排进入Li^+格位,大幅提升811基体可逆容量;Mg^(2+)、Al^(3+)掺杂进一步增强基体晶格稳定性,改善其循环性能;Li^+-Al^(3+)共掺杂使之达到最佳:首次充电效率ICE超过90%,0.2C倍率下50次循环容量达195.8 m Ah/g、容量保持率为96.2%.
基金the Natural Science Foundation of Heilongjiang, China(Grant No.E2004-24).
文摘LiNi0.78 Co0.2 Al0.02O2 cathode materials were prepared with a novel co-precipitation method followed by heat-treating. The properties of the materials were characterized. XRD patterns showed that no secondary phase appeared and the hexagonal lattice parameter c of LiNi0.rsCoo.2AI^0202 was larger than that of LiNi0.8Co0.2O2. The SEM images indicated that the powders of the material were submicron size. The results of the ICP-AES analysis proved that elemental compositions of the material were similar to those of the targeted one. Cyclic voltammetry （3.0- 4. 2 V） illustrated that the new material had good lithium-ion intercalation/de-intercalation performance. The results of galvanostatic cycling showed that the initial specific discharge capacity of the prepared material was 181.4 mAh/g, and the specific discharge capacity was 177.3 mAh/g after 100 cycles （0. 2C, 3.0 - 4. 2 V, vs. Li^＋/Li） with the capacity retention ratio of 97.7%.
基金Supported by the Project of Shanghai Committee of Science and Technology,China(Nos.1052nm00100,09ZR1437600)
文摘Several lithium-ion batteries of 18650-type were assembled with pristine or Al2O3-coated LiNi0.4Co0.2Mn0.4O2（NCM） as cathode material and mesocarbon microbeads（MCMB） as anode material.The cycling performance of the batteries was examined under 25 °C at a 2C rate within a potential range of 2.75―4.20 V.The changes of the crystal structure,the lattice parameter,the mean crystallite size,and the mean micro-strain of pristine NCM and Al2O3-coated NCM during the charge-discharge cycling were determined by X-ray diffraction（XRD）.The results indicate that the bulk structure of Al2O3-coated NCM is more stable than that of pristine NCM,which leads to the better cycling performance of Al2O3-coated NCM compared to that of pristine NCM.
