To meet the development needs of high-performance and low-cost lithium-ion batteries, lithium-rich Co-free manganese-based cathode materials have become the primary choice for future power batteries based on the advantages of low cost and improved battery performance. Herein, Li1.2Mn0.6Ni0.2O2 is prepared by the high-temperature solid-state method. The impacts of calcination temperature, holding time, and heating rate on the microstructure and properties of cathode materials are systematically studied via orthogonal experiments. Results revealed that Li1.2Mn0.6Ni0.2O2 prepared by the high-temperature solid-state method at a calcination temperature of 900 °C, holding time of 12 h, and heating rate of 15 °C/min is ideal, with a smaller particle size and uniform particle distribution and a lower agglomeration degree, and the initial discharge specific capacity reaches 148.4 mAh·g−1 at 0.1 C. The discharge specific capacity of 102.8 mAh·g−1 is still maintained after 100 charge–discharge cycles. Among the various factors, holding time has the greatest influence on the lithium-rich Co-free manganese-based cathode material. The crystallinity, electrochemical properties, and microstructure of the material prepared at 12 h were considerably better than those prepared under other conditions. Test findings show that with a small particle size and uniform distribution, the synthesized cathode material has better rate and cycle performances.

Li-rich Co-free Mn-based cathode materials have attracted considerable attention in the development of lithium- ion batteries (LIBs) due to their impressive theoretical capacity and cost-effectiveness. Nevertheless, the inherent shortcomings in cycling stability and rate capability hinder their widespread application. Herein, Na-doped Li 1.2- xNaxMn0.6Ni0.2O2 (x = 0, 0.01, 0.03, 0.05, 0.08, 0.10) is synthesized using Na2CO3 as the source of Na. Density functional theory (DFT) calculations reveal that the presence of Na+ introduction enlarges the between-layer spacing of Li 1.2 Mn 0.6 Ni 0.2 O 2 , reduces the band gap width, reduces the cation mixing phenomenon, and increases the Li+ diffusion rate and electronic conductivity. Experimental electrochemical assessments demonstrate that the cathode material with a Na doping level of 0.03 exhibits remarkable performance: it achieves a discharge specific capacity of 204 mAh center dot g-1 at 0.1C and retains 87.4% of its capacity after 100 cycles. These findings underscore the efficacy of Na doping in enhancing the electrochemical properties of Li-rich Mn-based cathode materials, thereby advancing their potential for practical application in LIBs.

Cobalt-free manganese-based lithium-rich layered oxides (LLOs) have garnered research attention as prospective lithium-ion cathode materials owing to their large specific capacity and low price. However, their large-scale application is hindered by their low Coulombic efficiency, poor cycling performance, voltage attenuation, and structural phase transition. To address these issues, the LLO structure is modified via Ti doping at the manganese site herein. Ti-doped Li1.2Mn0.6−xTixNi0.2O2 (x = 0, 0.03, 0.05, 0.10, and 0.15) is prepared using the high-temperature solid-state method. The Ti-doped Li1.2Mn0.6Ni0.2O2 is calculated via first principles. The results show that Ti4+ doping improves the cycle stability and rate performance of Li1.2Mn0.6Ni0.2O2. Electrochemical test results show that the sample exhibits enhanced electrochemical performance when the Ti doping amount is 0.05. The discharge specific capacity at 0.1C is 210.4 mAh·g−1, which reaches 191.1 mAh·g−1 after 100 cycles, with a capacity retention rate of 90.7%. This study proves the feasibility of using cheap cobalt-free LLOs as cathode materials for LIBs and provides a novel system for exploiting low-cost and high-performance cathode materials.

Li-rich Mn-based Co-free layered oxides (LLOs) are promising cathode materials for lithium-ion batteries (LIBs). However, they exhibit capacity loss and low initial Coulombic efficiency. Herein, an F-doped Li 1.2 Mn 0.6- Ni 0.2 O 1.9 F 0.10 material has been prepared by the high-temperature solid-state method, with numerous oxygen vacancies on the surface to accelerate Li + transport. The electrochemical performance of Li 1.2 Mn 0.6 Ni 0.2 O 1.9 F 0.10 considerably improved after the treatment. A high-capacity retention of 86.9 % after 100 charge/discharge cycles at 1C was achieved for Li 1.2 Mn 0.6 Ni 0.2 O 1.9 F 0.10 . Results revealed that F doping replaces part of O2-, forming more force between the TM-F bonds (compared to the TM-O bond), which inhibits the cation mixing phenomenon. The layered structure stability of the material is improved after F doping, and the migration energy barrier of Li+ is reduced, which promotes the migration of Li+, thereby improving the electrochemical performance of Li 1.2 Mn 0.6 Ni 0.2 O 2 .

In this study, the LiFePO4 cathode was synthesized by the ionic thermal method using the deep eutectic mixture of tetramethyl ammonium chloride and urea. The synthetic conditions were systematically investigated by orthogonal experiments, which indicate that the optimal reaction time, reaction temperature, molar ratio of Li to DES and rotate speed are 96 h, 220 °C, 1:14 and 20 r·min −1, respectively. X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) were characterized to investigate the crystalline structure and morphology of the obtained materials, indicating well-crystallized LiFePO4 with olivine structure. And the physical properties of LiFePO4 were explored through Fourier transform infrared spectroscopy (FTIR), 57Fe Mössbauer absorption spectra and Raman spectra. An initial discharge capacity can reach 151 mAh·g−1 at 0.1C rate for LiFePO4 following by calcining at 600 °C under the optimal conditions, and it retains 125.1 mAh·g−1 after 100 cycles. These results demonstrated that the addition of ionic liquids can improve the rate performance, cycle performance and ion diffusion rate of LiFePO4.

Li2MnSiO4 is considered a novel cathode material for lithium-ion batteries, due to its high theoretical capacity, outstanding safety performance, environmentally friendly nature, and low cost. In this study, Li2MnSiO4 was synthesized using sol-gel method as a potential high-performance cathode material for lithium-ion batteries (LIBs). The effects of the molar ratio of lauric acid, molar ratio of ethanol, and firing temperature and firing time on Li2MnSiO4 were systematically studied by orthogonal test. The optimum conditions for the synthesis of Li2MnSiO4 by sol-gel method were determined as follows: the ratio of lauric acid to Li2MnSiO4 was 3:2, the ratio of ethanol to Li2MnSiO4 was 3:1, the firing temperature was 650°°C, and the firing time was 10 h. The initial discharge capacity of Li2MnSiO4 as the positive electrode of the lithium-ion battery during the optimization process can reach 158.5 mAh/g within a wide voltage range of 1.5–4.5 V. The results show that the discharge capacity and cycle performance of Li2MnSiO4 can be improved by adding lauric acid and glycol.

Lithium aluminate (LiAlO2) has been successfully synthesized by a hydrothermal reaction based on using the anodic alumina (AAO) as the template and explored as the compound materials in LiMnPO4/C lithium battery. LiAlO(2)nanoplate porous structure is inherited from anodic aluminum oxide (AAO) structure and serves as substrates to grow LiMnPO(4)nanocrystals, which provide a high surface area with a porous structure. The morphology, structure, and electrochemical properties of the samples were analyzed. The instruments used in this process are X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM), and charge-discharge test system. The crystallization transition process of the precursor after hydrothermal reaction was researched by thermal gravity analysis. The specific surface area and pore volume of LiAlO(2)are 118.6 m(2)/g and 0.89 cm(3)/g, which were confirmed by the method of nitrogen adsorption. Moreover, the 10% content LiAlO2-LiMnPO4/C has the excellent electrochemical performance, and its first discharge capacity is 144 mAh/g at 0.1 C, compared with the LiMnPO4/C electrode (121 mAh/g at 0.1 C). The LiAlO(2)can obstruct the direct contact of electrode and electrolyte, thus reducing their direct contact areas of cathode at charged state, owing to the fact that LiAlO(2)around the active surfaces of LiMnPO(4)grains acts as an ionic conductive wiring.

The sol-gel method is adopted for synthesizing LiFePO4/H2Ti3O7 and LiFePO4/TiO2 nanocomposites and contrasted them with different content. The crystal structure and morphology of the as-synthesized samples are characterized via X-ray diffraction and scanning electron microscope techniques, respectively. It is demonstrated that the structure of composite materials is a single olivine structure without any impurity phases. The specific surface area and pore size of H2Ti3O7 and TiO2 are analyzed using the BET surface area technique and the BJH method, which exhibits that the higher specific surface area is very beneficial to the diffusion of lithium ion. Also, the electrochemical properties are tested by the charge-discharge tests. Two composites show fascinating cycle capacity and charge-discharge performance when the amount of H2Ti3O7 and TiO2 is 1%. Among them, 1% H2Ti3O7 presents a better performance at 0.5 C. The sample delivers a discharge capacity of 161.1 mAh g−1 (105.83% of the initial capacity is kept after 50 cycles). In conclusion, the proper addition of H2Ti3O7 and TiO2 can effectively facilitate the lithium ion diffusion rate to enhance the electrochemical properties of composites.

The sol-gel method is adopted for synthesizing LiFePO 4 /H 2 Ti 3 O 7 and LiFePO 4 /TiO 2 nanocomposites and contrasted them with different content. The crystal structure and morphology of the as-synthesized samples are characterized via X-ray diffraction and scanning electron microscope techniques, respectively. It is demonstrated that the structure of composite materials is a single olivine structure without any impurity phases. The specific surface area and pore size of H 2 Ti 3 O 7 and TiO 2 are analyzed using the BET surface area technique and the BJH method, which exhibits that the higher specific surface area is very beneficial to the diffusion of lithium ion. Also, the electrochemical properties are tested by the charge-discharge tests. Two composites show fascinating cycle capacity and charge-discharge performance when the amount of H 2 Ti 3 O 7 and TiO 2 is 1%. Among them, 1% H 2 Ti 3 O 7 presents a better performance at 0.5 C. The sample delivers a discharge capacity of 161.1 mAh g −1 (105.83% of the initial capacity is kept after 50 cycles). In conclusion, the proper addition of H 2 Ti 3 O 7 and TiO 2 can effectively facilitate the lithium ion diffusion rate to enhance the electrochemical properties of composites.

In this study, Li2FeTiO4 was prepared as a promising cathode material for Li–ion batteries via simple hydrothermal process using commercial C2H3O2Li·2H2O, FeSO4·7H2O, and C16H36O4Ti as raw materials. The synthesis conditions, including temperature, time of hydrothermal synthesis, molar ratio, and pH value, were optimized based on an orthogonal experimental design. The optimal molar ratio, reaction temperature, reaction time, and pH were 4:1:1, 175 °C, 48 h, and 7, respectively. X-ray diffraction and scanning electron microscopy confirmed the formation of the product. The specific surface area (9.814 m2/g) of Li2FeTiO4 samples calcined at 700 °C was measured via nitrogen adsorption/desorption isotherms, demonstrating the potential application of Li2FeTiO4. The sample prepared at optimal conditions and calcined at 700 °C exhibits a high initial specific capacity of 153.8 mAh/g at a rate of C/10. The heat-treated Li2FeTiO4 has a stable cycling performance owing to its unique morphology and good crystallinity, which was achieved during calcination.