The electrochemical performance of the materials was improved by preparing Li6.4La3Zr1.4Ta0.6O12 (LLZTO) coatings on the surface of Li1.2Mn0.54Co0.13Ni0.13O2 (LMRO) particles. Morphological measurements indicate the presence of a coating formed by the aggregation of a large number of LLZTO nanoparticles on the surface of pristine LMRO particles. Electrochemical test results show that the material with LLZTO coating has smaller polarization and lower charge transfer impedance. After 100 cycles at 1C, the capacity retention of the material with (2%wt) LLZTO coating was 89.68%, while the capacity retention of the LMRO original was 80.14%.

AbstractSodium‐ion batteries (SIBs) have been considered as promising replacements to lithium‐ion batteries (LIBs) for large‐scale energy storage applications. For anode materials, titanium dioxide (TiO2) as a typical insertion‐type anode material have been extensively investigated as a safety, stable, cheap and environmental‐friendly anode materials for SIBs. Constructing suitable TiO2 crystal structure is a common modification strategy for improving the diffusion kinetics of sodium ion within TiO2 and its intrinsic electronic conductivity. Herein, a multi‐atomic doped oxygen‐deficient TiO2/C composites (N, S‐NTC) was successfully synthesized with excellent electrochemical performance. Synergistic effect of N, S and Ni elements on the structure, morphology and electrochemical performance was investigated. Electron Paramagnetic Resonance (EPR) spectroscopy, Raman spectroscopy and X‐ray photoelectron spectroscopy (XPS) analysis indicated that the Ni, N, S doping can introduce oxygen deficiency, narrow the bandgap of TiO2 and facilitating Na+ diffusion, further providing higher electronic/ionic conductivities and faster electron transport channel. As a consequence, the anode materials delivered ultrahigh rate performance and cycling performance of a high reversible capacity of 128.6 mA h g−1 at 1 A g−1 after 3000th cycles.

以活性炭和偏高岭土为原料、水玻璃和氢氧化钠为激发剂,采用悬浮固化法制备了活性炭/地质聚合物复合微球(GMC)吸附剂,通过X射线衍射仪、扫描电镜和紫外-可见分光光度计研究了其微观结构以及对刚果红(CR)和结晶紫(CV)的吸附性能.结果表明,GMC的吸附性能随活性炭添加量增加而提高,活性炭添加量为30％时,其对CR和CV的吸附过程符合Langmuir吸附模型和准二级动力学模型,理论最大吸附量分别为61.88 mg/g和104.06 mg/g,循环再生使用5次后对CR和CV的去除率依然可达71.73％和75.65％.

试验采用高温固相法经二次烧结合成622三元正极材料.研究在烧结时间、烧结温度不变的情况下,探究不同Al掺杂量对622三元正极材料性能的影响.试验结果显示,Al添加量为0.5％,622三元正极材料的综合性能最佳.此时622三元正极材料的振实密度为2.62 g/cm3,粒度为10.58μm,容量为167.12 mAh/g,容量保持率为98.48％,达到最佳掺杂效果.试验结果对于622三元正极材料的改性具有一定的参考意义.

试验以纳米二氧化钛为掺杂原料,采用高温固相合成法,制备二氧化钛改性锰酸锂正极材料.分别以0.00％、0.15％、0.25％、0.50％、0.70％的Ti元素掺入比例进行掺杂,结果显示掺杂后的锰酸锂材料其循环性能得到了很大的改善,Ti掺杂量为0.25％的条件下合成的锰酸锂材料所制备得的锂离子电池的综合性能最优,此时锰酸锂材料的振实密度为2.10 g/cm3,压实密度为3.14 g/cm3,容量为115.69 mAh/g,50次循环1C容量保持率为93.17％.

A rod-like Li-rich manganese layered oxide cathode material Li1.2Mn0.54Ni0.13Co0.13O2 is synthesized through beta-MnO2 template by a simple solid-state reaction, and the reacting process and electrochemical properties are studied. The results show that the radial nanometer effect and inherent structural stability of beta-MnO2 nanorods bring about fast chemical reaction, morphologic heredity and service toleration. The unique architecture of the rod-like Li1.2Mn0.54Ni0.13Co0.13O2 also results in superior layered structure with low cation mixing and excellent electrochemical performances. The initial discharge capacity is about 250 mAh g(-1) and the capacity retention rate is about 76.0% after 80 cycles at 0.1 C current rate. When cycled at 2 C rate, the discharge capacity is as high as 175.3 mAh g(-1), suggesting a good rate capability. The capacity decline is mainly attributed to the radial direction nanometer effect, structural transformation, cation mixing and surface degradation. (C) 2021 Elsevier B.V. All rights reserved.

The huge capacity loss during cycling is the main obstacle to the industrial application of nickel-rich cathode materials Li[Ni1?x?yCoxMny]O2 (NCM, 1 ? x ? y 0.8). However, at the same nickel content, another nickel rich Li[Ni1?x?yCoxAly]O2 (NCA, 1 ? x ? y > 0.8) materials possess a much better cyclic performance due to the more powerful bond of Al-O compared with the NCM. But NCA yields a lower capacity caused by inactive Al. In this study, using the spray pyrolysis method to fabricate the new quaternary nickel-rich cathode material LiNi0.8Co0.1Mn0.1?xAlxO2 (NCMA, 0 < x < 0.06) is proposed to enhance the cyclic performance of NCM and with a limited capacity decrease for the incomplete substitution of Mn. The materials exhibit the evidently improvements in the electrochemical performance, among which the LiNi0.8Co0.1Mn0.06Al0.04O2 materials present the most excellent performances where the capacity retentions are up to 83.8% (3.0?4.4 V, 25 ?C) after 200 cycles and 88.0% at 55 ?C after 100 cycles. The satisfying results can be attributed to the inhibition of oxygen release and cationic disorder after the Al introduced, which are strongly confirmed by the results of structure refinement and first principles calculation.

LiNi0.6Mn0.2Co0.2O2 is considered as a promising Ni-rich layered cathode material of lithium-ion batteries due to low cost and high capacity. However, it is generally prepared by complicated precursor methods. In this work, LiNi0.6Mn0.2Co0.2O2 is synthesized by a solid-state method with manganese acetate as manganese source and an effective mixing way. The as-prepared samples are characterized by XRD, FESEM, XPS and electrochemical techniques. The results show that the synthesized LiNi0.6Mn0.2Co0.2O2 cathode materials have an alpha-NaFeO2 type structure with insignificant cation mixing, octahedral single crystal and quasi sphere morphology, smaller particle size and good dispersion, so that it displays an initial discharge capacity of 163.6 mAh g(-1) with a coulombic efficiency of 85.6% at 0.1C, a capacity retention of 99.1% after 100 cycles at 0.5C and an excellent rate performance, and also an initial discharge capacity of 177.3 mAh g(-1) with capacity retention of 94.6% after 155 cycles at 55 degrees C. (c) 2020 Elsevier B.V. All rights reserved.

以四氧化三锰和碳酸锰为原料,加入五氧化二铌添加剂,采用高温固相合成锰酸锂,在40 m轨道窑炉和马弗炉分别进行温度不同、掺铌量不同的烧结实验,在改变烧结窑炉的情况下,对其烧结样进行理化性能分析、扣电性能分析.结果表明:40 m轨道窑炉烧结的实验样品要比马弗炉烧结的实验样品性能要更加良好,此时,可以得出实验的n(Li)/n(Mn)摩尔最佳配比为0.54,五氧化二铌掺杂量为0.7％,烧结温度为780℃.此时获得的最好结果为:1 C的放电容量为126.7 mA·h/g,50次循环保持率为94.46％,压实密度为3.08 g/cm3,D50为14.15μm.该试验为生产高压实密度、高容量型锰酸锂提供依据.

采用高温固相法在相同条件下合成了LiNi0.6Co0.1Mn0.3O2与LiNi0.6Co0.2Mn0.2O2正极材料,利用XRD、SEM表征了材料的结构与形貌,通过恒电流充放电测试、循环伏安(CV)和交流阻抗(EIS)研究了其电化学性能.结果 表明,室温条件下以0.2 C倍率在3.0～4.3 V电压范围内,LiNi0.6CO0.1Mn0.3O2的首次放电比容量为171.8 mAh/g,1C循环100次后容量保持率为78.5％;LiNi06Co0.2Mn0.2O2的首次放电比容量为174.6 mAh/g,1C循环100次后容量保持率为83.0％.CV与EIS测试表明,相比LiNi0.6Co0.2Mn0.2O2,LiNi0.6Co0.1Mn0.3O2材料有更大的极化与电荷转移阻抗.

采用高温固相法合成了不同铝含量的523镍钴锰酸锂,通过振实密度、粒度分布、pH值、电化学性能测试等手段,探究不同铝掺杂量、烧结时间、烧结温度对高电压镍钴锰酸锂性能的影响.研究结果表明,当铝掺杂量为0.7％、烧结时间为10 h、烧结温度为940℃时,高电压镍钴锰酸锂的性能最佳,此时,样品粒度D50为7.83μm,振实密度达到2.81 g/cm3,在3.0～4.4 V电压范围和1.0C倍率下,初始容量为174.17 mAh/g,50次循环容量保持率为97.18％.试验结果对改善高电压镍钴锰酸锂性能有一定的参考作用.

In weak acidic medium, silicate can with ammonium molybdate to form soluble yellow silicon molybdenum heteropoly acid , the heteropoly acid ammonium ferrous sulfate can be reduced into silicon molybdenum blue, in weak acid medium, silicate can yellow silicon molybdenum heteropoly acid and ammonium molybdate to form soluble, the heteropoly acid ammonium ferrous sulfate can be reduced into silicon molybdenum blue content at the wavelength of 680nm under the condition of UV spectrophotometric in Manganese peach, and the method of the analysis conditions were optimized. The experimental results show that the recovery in the determination of manganese in peach method was 99.88%-102.3%, among multiple determination of the relative standard deviation was 0.1139%, the detection limit is 0.0264 g/mL. This method has good precision, high recovery and high feasibility. It is suitable for the determination of silicon content in manganese peach.

通过实验探究异丙醇铝包覆镍钴锰酸锂三元材料对镍钴锰酸锂三元材料微观组织与性能的影响.并且通过TD、压实密度、粒度分布、可溶锂含量测试、电学性能测试等分析手段对合成的523镍钴锰酸锂的各种性能进行分析研究,通过对实验数据进行对比和分析可以得出:在实验中添加异丙醇铝(C9H21AlO3)的包覆量为0.5％、烧结温度700℃、且时间为8 h的条件下,材料性能得到了进一步的提升.包覆过后的三元材料相关性能指标为:平均粒度为13.5μm、1.0 C容量达到156.2 mA·h/g,充放电50次后电池的容量保持率为99.03％.

Na3V2(PO4)3/C nanofibers are prepared by a pre-reduction assisted electrospinning method. In order to maintain the perfect fibrous architecture of the Na3V2(PO4)3/C samples after calcining, a series of heat treatment parameters are studied in detail. It is found that the heat treatment process shows important influence on the morphology and electrochemical performance of Na3V2(PO4)3/C composite nanofibers. Under the calcining conditions of 800°C for 10 h with a heating rate of 2.5°C min-1, the well-crystallized uniform Na3V2(PO4)3/C nanofibers with excellent electrochemical performances are successfully obtained. The initial discharge specific capacities of the nanofibers at 0.05, 1, and 10C are 114.0, 106.0, and 77.9 mAh g-1, respectively. The capacity retention still remains 97.0% after 100 cycles at 0.05C. This smooth, uniform, and continuous Na3V2(PO4)3/C composite nanofibers prepared by simple electrospinning method, is expected to be a superior cathode material for sodium-ion batteries.

Single-crystal magnesium-doped spinel lithium manganate cathode materials are prepared by the hydrothermal method followed by the heat treatment. XRD patterns reveal that Mg2+ions have already diffused into the Li1.088Mn1.912O4 crystal structure and not affect the Fd3m space group. SEM images demonstrate that the magnesium-doped spinel lithium manganates show uniform polyhedral single crystals with 2–4 μm. Electrochemical performance demonstrates that the optimized composition of Li1.088Mg0.070Mn1.842O4 electrode exhibits the best electrochemical properties. It delivers 92.0 mAh g−1 at 8C rates and corresponds to 90.8% capacity retention (vs. 1C), far higher than those of the pristine electrode (70.4 mAh g−1 and 69.2%). In addition, the Li1.088Mg0.070Mn1.842O4 electrode also shows 95.5% capacity retention after 100 cycles at 1C, while the pristine electrode only shows 91.0% capacity retention. The excellent electrochemical performances of Li1.088Mg0.070Mn1.842O4 electrode are ascribed to the suppressed polarization, more stable crystal structure, and better kinetic characteristics.

采用固相烧结法,研究不同烧结工艺以及包覆改性处理对LiNi0.5Co0.2Mn0.3O2三元材料性能的影响.采用XRD、SEM、比表面积、振实密度以及电性能分析,发现以650℃/4 h→780℃/10h进行第一次烧结后,然后在880℃/8h复合包覆0.2％纳米级氢氧化镁和0.2％纳米级钛白粉的材料,获得最优的综合电性能,比容量可达156.2 mAh/g,1 C3.6V放电平台为27 min,50周循环后容量衰减仅有0.93％.

Cobalt and nitroso R salt can produce soluble red complex in pH =5.5 acetic acid sodium acetate buffer,at the absorption wavelength of 530 nm,the content of cobalt in LiCoxNiyMn1-x-yO2 is analyzed by matrix matching high concentration differential spectrophotometry.The analysis conditions of the method are optimized.The experimental results show that the recovery rate of cobalt in LiCoxNiyMn1-x-yO2 is 95.19％ ～98.30％,and the relative standard deviation is less than 0.605％.The method is simple,fast and satisfactory.

LiNi0.6Co0.2 Mn0.2O2, an alpha-NaFeO2 type layered lithium transition metal oxide, is deemed as one of the most promising cathode materials for lithium-ion batteries. To ascertain the structural evolution and formation mechanism of this compound during high-temperature solid-state synthesis, thermal and structural analysis methods were performed, confirmed with the characterization of morphology and lithium residue. LiOH, used as the lithium source, showed both a lower initial temperature and a lower degree of lithium intercalation compared to Li(2)CO(3 )when reacting with the precursor. A higher temperature for Li2CO3 and a longer reaction time for LiOH during sintering would be beneficial to the material synthesis. Furthermore, a pre-heat treatment process in the temperature range of 400-600 degrees C is beneficial for the lithium intercalation reaction.

LiNi0.6Co0.2Mn0.2O2 powder was synthesized by solid-state sintering method by using Ni0.6Co0.2Mn0.2(OH)2 and Li2CO3 as the raw materials.The effects of reaction temperature on the physical properties and electrochemical performance were investigated by X-ray diffraction and scanning electrodmicroscope and electrochemical tests.The results showed that the XRD pattern of the sample prepared under the above condition can be identified by a typical structure of hexagonala-NaFeO2 type.After reaction at 880℃ for 20 h,LiNi0.6Co0.2Mn0.2O2 shows the best electro-chemical performance.In the voltage range of 3.0～ 4.3 V,the materials' discharge capacities reached 188 mA · h/g at the rate of 0.1 C.After 10 cycles at 1.0 C rate,the capacity retention was 95.46％.