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To realize the high value–added utilization of acid-washed iron red, in this paper, acid-washed iron red is used as raw material. Aiming at the problem of low conductivity of iron-based lithium ion batteries (LIBs) LiFePO4/C materials, different metal ions are doped in the iron position, and the microstructure and electrochemical properties of the obtained material are systematically studied. Here, LiFePO4/C is synthesized through simple carbothermal reduction method using acid-washed iron red as the iron source. On this basis, La (1%, 2%, 3%) doping modification is carried out. Then doped modification is performed on this basis, preferably 2% La-doped LiFePO4/C materials. The XRD patterns show that the diffraction peaks of the samples prepared at all doping amounts can be perfectly matched with the standard card (PDF # 40–1499), and there is no impurity peak, all of which are pure phases. According to the refined data, it is clear that minor amount of La has successfully replaced the position of Fe and incorporated into the lattice. Electrochemical tests show that LiFe0.98La0.02PO4/C has the highest charge and discharge capacity of 146.5/138.2 mAh·g−1 in the first cycle at 0.5C, and the reversible specific capacity of 136.5 mAh·g−1 remains after 50 cycles. Furthermore, the first-principles calculations more strongly confirm that La doping can significantly improve the defects of low electronic conductivity of LiFePO4. [ABSTRACT FROM AUTHOR]

In order to better recycle and reuse metal ions in metallurgical industrial waste and reduce the production cost of lithium-ion batteries (LIBs). In this paper, carbon-coated LiFePO4/C cathode materials are synthesized through the carbothermal reduction method using acid-washed iron red as raw material. In order to make LiFePO4/C exhibit satisfactory electrical properties, the rare earth element Eu is doped in the Fe position, and the doping amount is optimized. The influence of the double coupling effect of coating and doping on the structure and properties of LiFePO4 cathode materials is systematically discussed. The local XRD results of the doped samples show that the diffraction peaks of the doped samples move to the small angle grain boundaries, and the lattice spacing of the materials increases, which is due to the large radius of Eu ions. The experimental results show that the dual coupling of carbon coating and ion doping can improve the conductivity of LiFePO4 cathode materials and improve its electrochemical performance. When the doping amount of Eu is 2%, the electrochemical performance of LiFe0.98Eu0.02PO4/C cathode material is the best. The initial charge–discharge capacity of 153/144.4 mAh·g−1 can be obtained at 0.5C, and a discharge capacity of 143.2 mAh·g−1 remains after 50 cycles. The exploration of this experiment provides a reasonable solution for slowing down the pollution of metallurgical waste to the environment and reducing the production cost of LIBs. [ABSTRACT FROM AUTHOR]

ZnMn2O4 anode material with nanosheet lamellar structure was synthesized using microwave method. The bearing of reaction temperature, reaction time, reactant compactness, and pH of the synthesis environment on the discharge–charge performance of samples were systematically studied. It is confirmed that ZnMn2O4 material presents a nanosheet lamellar structure with a uniform distribution. When the reaction temperature is 200℃, the reaction time is 25 min, reactant compactness is 73%, pH is 7, and initial discharge-specific capacity of the samples is 959.6 mAh·g−1. After 40 cycles, the capacity remains at 346.9 mAh·g−1, and the coulomb efficiency is stable at 100%. Spinel ZnMn2O4 anode material was microwave hydrothermally synthesized from zinc nitrate and manganese nitrate as raw materials in an aqueous solution. The material has a nano lamellar structure and shows good electrochemical properties as anode material of lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Summary: The urchin‐like NiCo2O4 material was prepared by a one‐step hydrothermal method. The optimal synthetic conditions were systematically investigated by an orthogonal test method and single factor of hydrothermal time to evaluate the influence of sample morphology and electrochemical performance. The synthesis conditions for preparing NiCo2O4 with different morphologies were systematically studied. In the single factor experiment, when the hydrothermal time is 6, 12, 16, and 24 hours, the corresponding morphologies are urchin‐like (NCO‐U), flower‐like (NCO‐F), sheet‐like (NCO‐S), and block‐like (NCO‐B), respectively. The element content of the prepared materials under different synthesis conditions was tested by an inductive‐coupled plasma emission spectrometer, and an interesting phenomenon was found. As the reaction time increases, the content of Ni+ gradually decreases and the content of Co+ gradually increases, which may be one of the factors that affect the morphology and electrochemical performance of the material. The specific capacitances of NCO‐U, NCO‐F, NCO‐S, and NCO‐B are calculated to be 914.3, 392.2, 313.3, and 277.4 F g−1, respectively, at a current density of 1 A g−1. Benefiting from the large specific surface area and rich oxygen vacancy, the as‐fabricated urchin‐like NiCo2O4 as electrode materials for supercapacitor demonstrates its promising application potential for supercapacitors. [ABSTRACT FROM AUTHOR]

Summary: In this work, Li2Mn1–xCrxSiO4 cathode material was synthesized by the solid‐phase doping method and two‐step calcination. The appropriate calcination temperature can be obtained by TG‐DTA curve. XRD, SEM and TEM tests show that the prepared Li2Mn1–xCrxSiO4 has a Pmn21 space group structure, and the particle size decreases from 570 to 140 nm with the increase of the doped Cr content. Cr doping enhances the structural stability of Li2Mn1–x CrxSiO4 and improves the electrochemical activity of the cathode. The results of XRD, EDS and XPS show that Cr3+ is successfully doped into the Li2MnSiO4 lattice, and the element distribution is uniform. The electrochemical results show that Li2Mn0.8Cr0.2SiO4 exhibits significantly enhanced cycle stability and discharge capability. [ABSTRACT FROM AUTHOR]