Synthesis and electrochemical properties of layered Li[Ni0.333Co0.333Mn0.293Al0.04]O2−zFz cathode materials prepared by the sol–gel method

The cathode-active materials, layered Li[Ni_0.333Co_0.333Mn_0.293Al_0.04]O_2−zF_z (0 ≤ z ≤ 0.1), were synthesized from a sol–gel precursor at 900 °C in air. The influence of Al–F co-substitution on the structural and electrochemical properties of the as-prepared samples was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and electrochemical experiments. The results showed that Li[Ni_0.333Co_0.333Mn_0.293Al_0.04]O_2−zF_z has a typical hexagonal structure with a single phase, the particle sizes of the samples tended to increase with increasing fluorine content. It has been found that Li[Ni_0.333Co_0.333Mn_0.293Al_0.04]O_1.95F_0.05 showed an improved cathodic behavior and discharge capacity retention compared to the undoped samples in the voltage range of 3.0–4.3 V. The electrodes prepared from Li[Ni_0.333Co_0.333Mn_0.293Al_0.04]O_1.95F_0.05 delivered an initial discharge capacity of 158 mAh⁻¹ g and an initial coulombic efficiency is 91.3%, and the capacity retention at the 20th cycle was 94.9%. Though the F-doped samples had lower initial capacities, they showed better cycle performances compared with F-free samples. Therefore, this is a promising material for a lithium-ion battery.     

刚果(金)硫化铜矿与水钴矿的联合浸出工艺研究

以刚果(金)硫化铜矿和水钴矿为原料,提出了硫化铜矿和水钴矿两矿联合浸出提取钴和铜的新工艺。结果表明,在硫化铜矿与水钴矿两矿质量比为0.4、初始硫酸浓度2.5mol/L、液固比5(mL/g)、温度80℃、反应时间5h的条件下,钴、铜浸出率分别达到98.80%和96.01%。     

电池级硫酸钴生产工艺研究进展

综述了7种含钴原料生产电池级硫酸钴的工艺技术。含钴原料不同,生产电池级硫酸钴的工艺技术也有较大差别。根据含钴原料特性将含钴原料细分为7种:含钴氧化矿、含钴硫化矿、副产钴渣、含钴合金废料、废钴催化剂、钴中间品、含钴电池废料。以含钴原料为出发点,对各种含钴原料生产电池级硫酸钴的工艺进行了综述。详细介绍和总结了浸出和精炼工艺的进展,并展望了电池级硫酸钴生产工艺的发展方向。     

合成具有高效光催化活性的片状β-Bi2O3的一种新方法

采用萃取-反萃-热分解法以辉铋矿的盐酸浸出液为原料制备了层片状的β-Bi₂O₃。所制备的样品分别用X衍射仪及透射电镜对其物相及形貌进行表征, 以罗丹明B为污染物研究了其光催化活性。结果表明: 所制备的β-Bi₂O₃是一种层状的纳米片, 具有较低的禁带宽度。在实验条件下, 对罗丹明B进行4 h的降解, 降解率达到99.23%, 样品的重复降解实验还表现出良好的循环稳定性。     

溶析结晶法制备硫酸钴的实验研究

采用溶析结晶法制备硫酸钴,考察了溶析剂种类、溶析剂用量、溶析剂浓度、溶液初始Co²⁺浓度、结晶温度等参数对硫酸钴结晶率的影响。以乙醇为溶析剂,在溶析剂与硫酸钴溶液体积比为1∶1、溶析剂浓度为95%、溶液初始Co²⁺浓度为120 g/L、结晶温度为25 ℃条件下,硫酸钴结晶率达到98.27%,母液中Co²⁺浓度为1.36 g/L。本方法制备的硫酸钴与蒸发结晶工艺制备的硫酸钴相比,在溶解pH值、水不溶物、磁性物、油分等关键指标方面具有明显优势,满足GB/T 26523-2011《精制硫酸钴》优等品的要求。     

Porous CoTiO3 microbars as super rate and long life anodes for sodium ion batteries

Porous CoTiO₃ microbars have been successfully prepared by a facile solution way followed by thermal annealing in air. When evaluated as electrode materials for sodium ion batteries, unique 1D porous structure demonstrates remarkable sodium storage properties. The resultant CoTiO₃ microbar electrodes exhibit not only higher discharge capacity (135.5?mA?h?g^?1 at 300?mA?g^?1 after 500 cycles), but also more enhanced rate performance compared to those of CoTiO₃ microparticle electrodes. The new findings reported here highlight the possibility for designing high-performance anode materials for sodium ion batteries.     

硝酸常压浸出红土镍矿特性及镍浸出动力学

采用ICP和XRD分析手段研究了某红土镍矿的元素及物相组成。采用硝酸常压浸出该红土镍矿。通过单因素条件实验和综合实验探究了硝酸浓度、固液比、搅拌转速、浸出时间、浸出温度在常压条件下对红土镍矿中Ni、Co、Fe和Mg浸出的影响,并求解了镍的浸出动力学。结果表明,该红土镍矿为硅镁型,在硝酸浓度5mol/L、固液比(g/mL)为1:12、搅拌转速250r/min、浸出时间150min、浸出温度85℃的条件下,Ni、Co、Fe和Mg的浸出率最佳,分别为98.75%、91.66%、81.45%、94.21%。镍的浸出过程符合收缩核模型,反应活化能为38.804kJ/mol,反应过程受化学反应和内扩散混合控制。     

镍钴锰三元前驱体废料与草酸钴废料的联合浸出

采用镍钴锰三元前驱体废料和草酸钴废料联合氧化还原浸出,研究了三元前驱体废料和草酸钴废料的质量配比、初始酸度、反应温度、反应时间等对镍、钴和锰浸出率的影响。结果表明,最佳反应条件为:三元前驱体废料和草酸钴废料的质量比53.5、初始酸度4mol/L、反应温度50℃、液固比41、反应时间120min,钴、镍和锰的浸出率分别达到96.76%、99.75%和99.80%,浸出液直接用于共沉淀法制备三元前驱体。实现了两种废料同时浸出和循环回收利用的目的。     

刚果(金)复杂铜钴合金两段浸出工艺研究

采用一段直接酸浸出-二段氧化酸浸工艺从复杂铜钴合金中浸出钴、铜、铁,考察了浸出工艺条件对铜、钴、铁浸出率的影响。结果表明,一段最佳浸出工艺条件为:液固比10∶1,温度85 ℃,硫酸初始浓度1.8 mol/L,搅拌转速 300 r/min,浸出时间2 h;二段最佳浸出工艺条件为:液固比10∶1,温度90 ℃,硫酸初始浓度4.0 mol/L,搅拌转速350 r/min,氯酸钠用量20%,浸出时间6 h。在此条件下,钴、铜、铁的总浸出率达96.99%、99.56%和98.16%。     

Morphology effect on electrochemical properties of doped (W and Mo) 622NMC, 111NMC,and 226NMC cathode materials

An investigation was carried out on layered Li(Ni_xMn_yCo_1−x−y)O₂ (NMC) cathode active materials for Li-ion batteries to determine the effect of morphology on their electrochemical performances. The NMC active materials were doped with Mo or W (2 wt%) in the study. Doped NMC cathodes with a ratio of 111, 622 and 226 (NiMnCo) were synthesized by spray pyrolysis which yielded aggregates were submicron size. A systematic investigation was performed, and two distinct morphology types were identified in active materials as a result. The first type was the aggregates which are densely packed composed of relatively smaller primary particles. The second type was the aggregates those packed loosely with larger primary particles. Our findings showed that the later morphology resulted in higher discharge capacity with lower internal resistance and, a shorter diffusion distance. Thus, the present study provides insights into the importance of morphology on electrochemical properties of layered cathode active materials.