Synthesis of LiNi1/3CO1/3Mn1/3O2 cathode material via oxalate precursor

Using oxalic acid and stoichiometrically mixed solution of NiCl2, CoCl2, and MnCl2 as starting materials, the triple oxalate precursor of nickel, cobalt, and manganese was synthesized by liquid-phase co-precipitation method. And then the LiNi1/3Co1/3Mn1/3O2 cathode materials for Li-ion battery were prepared from the precursor and LiOH-H2O by solid-state reaction. The precursor and LiNi1/3Co1/3Mn1/3O2 were characterized by chemical analysis, XRD, EDX, SEM and TG-DTA. The results show that the composition of precursor is Ni1/3Co1/3Mn1/3C2O4·2H2O. The product LiNi1/3Co1/3Mn1/3O2, in which nickel, cobalt and manganese are uniformly distributed, is well crystallized with a-NaFeO2 layered structure. Sintering temperature has a remarkable influence on the electrochemical performance of obtained samples. LiNi1/3Co1/3Mn1/3O2 synthesized at 900 ℃ has the best electrochemical properties. At 0.1C rate, its first specific discharge capacity is 159.7 mA·h/g in the voltage range of 2.75-4.30 V and 196.9 mA·h/g in the voltage range of 2.75-4.50 V; at 2C rate, its specific discharge capacity is 121.8 mA·h/g and still 119.7 mA·h/g after 40 cycles. The capacity retention ratio is 98.27%.     

Ni-P-多壁碳纳米管复合镀层的制备及摩擦磨损性能(英文)

采用湿式球磨对多壁碳纳米管(MWNTs)预处理,通过化学镀制备Ni-P-MWNTs复合镀层;对45钢、传统Ni-P镀层和Ni-P-MWNTs复合镀层在干摩擦条件下的摩擦磨损性能进行考察和比较。结果表明,球磨后MWNTs长径比降低,长度均匀,且多数端部处于敞开状态。与45钢和Ni-P镀层相比,Ni-P-MWNTs复合镀层的减摩耐磨能力显著强化。当复合镀层中MWNTs的质量分数为0.74%~1.97%时,其摩擦因数和磨损率随MWNTs含量的增加而减少;对于MWNTs质量分数为1.97%的复合镀层,其摩擦因数和磨损率仅为0.08和6.22×10?15m3/(N·m)。复合镀层优良的摩擦磨损性能归因于MWNTs优异的力学性能和自润滑特性。     

准一维铁镍合金材料的制备研究进展及应用展望

综述准一维铁镍合金材料(纳米棒、纳米线、纳米管、纳米纤维、纳米须)的各种制备方法和应用现状,主要介绍模板法、磁场引导羰基热分解法、还原法、微波等离子体法、溶胶-凝胶-热分解还原法、配位共沉淀-热分解法等,比较了各种制备方法的优缺点,介绍了其在相关领域的应用现状,最后展望其制备和应用的发展趋势。     

铁钴镍三元合金的制备研究进展

系统综述近年来铁钴镍三元合金在制备方法方面的研究进展,主要介绍机械合金化法、直流电弧等离子体法、电沉积法、模板法、还原法、溶胶凝胶-静电纺丝法、微乳液法、化学分解法和共沉淀-热分解法等,比较了各种制备方法的优缺点,并展望其未来研究的发展方向。     

Preparation and characterization of fibrous NiO particles by thermal decomposition of nickelous complex precursors

The influences of pyrolytic conditions, including temperature, time, the flow rate of air, and the heating rate, on the morphology, average size and specific surface area of the NiO particles were investigated, and the composition and morphologies of the products were characterized by using of XRD, SEM and BET. It is found that fibrous NiO particles were produced under the optimal conditions. A suitable range of pH for preparing dispersive precursors was chosen according to analysis of zeta potential. Based on the observations of NiO precursors growth and SEM morphology of the precursor, the oriented attachment was proposed for the well-aligned growth of the NiO precursor fibres. The final product NiO inherits the morphology of the precursor.     

氮掺杂碳包覆Bi2Mn4O10锂离子电池负极材料的制备及其电化学性能(英文)

为抑制高能锂离子电池负极材料Bi₂Mn₄O₁₀容量的快速衰减,通过简单球磨法制备新型高纯Bi₂Mn₄O₁₀/ECP-N(ECP-N为氮掺杂科琴黑)负极复合材料。所合成的Bi₂Mn₄O₁₀/ECP-N复合材料在0.2C倍率下循环100次后可保持576.2m A·h/g的比容量,容量保持率为75%,而纯Bi₂Mn₄O₁₀的容量保持率仅为27%。3C倍率下Bi₂Mn₄O₁₀/ECP-N复合材料的放电容量仍保持在236.1 m A·h/g。引入氮掺杂的科琴黑ECP-N不仅可以有效地提高比表面积以缓冲体积膨胀,增强材料的电导率和可湿性,而且还可以促进离子传输和可逆转化反应。     

草酸镍钴固溶体的制备与鉴别

以可溶性氯化镍、氯化钴和草酸或草酸铵为原料,氨水为pH值调节剂,采用液相共沉淀法合成草酸镍钴共沉淀产物,借助X射线衍射(XRD)、热重-差热分析(TG-DTA)和扫描电镜(SEM)对共沉淀产物进行表征,并将结果与机械混合物进行比较.结果表明:在共沉淀过程中,当溶液pH≤5.0时,钴离子易进入草酸镍晶格中形成置换固溶体,得到的共沉淀产物为草酸镍钴单相固溶体,其热分解行为明显不同于具有相同配比的机械混合物；当pH＞5.0时,镍离子和钴离子与草酸根离子的共沉淀过程为分步沉淀,得到的共沉淀产物为组分分布均匀的复杂混合物,而非单相固溶体.     

纤维状超细银粉前驱体制备热力学分析

根据同时平衡原理和质量平衡原理,从理论上推导出了Ag(Ⅰ)-C2O42--NH3-NH4+-H2体系中金属银离子和草酸盐在水溶液中热力学平衡的数学模型,计算并绘制出该体系的lg[Ag]T-pH图。在此基础上,分析液相沉淀过程中溶液的lg[Ag]T与pH之间的关系并推断出制备纤维状银粉前驱体粉末的理想pH值为5.0~6.0之间,为液相沉淀过程的实验操作提供了理论依据。最后通过验证实验证明了热力学计算结果的准确性。     

夹层中空结构铁酸镍粉末的制备及其吸波性能

NiFe2O4 powders with double skin structure which shows a length of 5 ?m and curved surface thickness of 0.5 ?m were prepared by thermal decomposition of their oxalate precursors. The NiFe2O4 powders were mixed uniformly with a proportion of paraffin and then pressed to composite samples. The 采用草酸盐沉淀法制备草酸铁镍前驱体,热分解得到长5 ?m、曲面厚0.5 ?m的夹层中空结构NiFe2O4粉末,将其与石蜡按一定比例混合均匀压制得NiFe2O4/石蜡复合物,考察了其电磁参数,计算了其吸波性能. 结果表明,NiFe2O4含量为40%(?)时复合物吸波性能最佳,样品厚度为3.5 mm时,材料在6.66 GHz处反射损失最小,为?52.06 dB,厚度为3.0 mm时,材料在6.98?8.59及9.72?10.84 GHz范围内反射损耗小于?10 dB,有效吸收频宽为2.73 GHz.     

形貌控制合成纤维状氧化亚镍粉末新型前驱体

以可溶性镍盐和草酸或草酸铵为原料, 利用氨为配位剂, 通过配位沉淀法制备了纤维状氧化亚镍粉新型前驱体, 并采用XRD、红外光谱(IR)和扫描电镜(SEM) 研究了前驱体粉末的物相、成分与形貌, 系统考察配位沉淀条件包括溶液pH值、反应温度、反应物浓度和表面活性剂对前驱体粉末形貌、粒度和成分的影响。结果表明: Ni(Ⅱ)-C₂O4^2--NH₃-NH₄⁺-H₂O反应体系中, 在溶液pH值为8.2～8.8, 温度为60～70 ℃, Ni²⁺浓度为0.5～0.8 mol/L, 表面活性剂聚乙烯吡咯烷酮(PVP)用量为0.1%～0.5%条件下得到的新型前驱体为草酸镍氨复盐, 其形貌为纤维状; 氨与镍离子配合并生成草酸镍氨复盐是纤维状形貌形成的内在机制。通过在空气中热分解该种前驱体即可得到比表面积为5.944 m²/g、轴径比大于50的纤维状氧化亚镍粉末。