1. Solvothermally synthesized Li(Ni0.6Co0.2Mn0.2)xCd1-xO2 cathode materials with excellent electrochemical performance for lithium-ion batteries
- Author
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Guicai Qi, Xiang Li, Yuan Zhou, Chunxi Hai, Shen Yue, Ren Xiufeng, Sun Yanxia, Luxiang Ma, Shengde Dong, and Zeng Jinbo
- Subjects
Materials science ,Scanning electron microscope ,General Chemical Engineering ,General Engineering ,General Physics and Astronomy ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Cathode ,0104 chemical sciences ,law.invention ,Chemical engineering ,chemistry ,X-ray photoelectron spectroscopy ,law ,Transmission electron microscopy ,Electrode ,General Materials Science ,Lithium ,0210 nano-technology ,Powder diffraction - Abstract
In this study, a Ni-Co-Mn-Cd-based precursor was synthesized using a solvothermal method and the Li(Ni0.6Co0.2Mn0.2O2)xCd1-xO2 cathode materials were prepared using a high-temperature solid-phase method. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were used to determine the morphology, structure, elemental composition, and electronic state of the pristine and Cd-doped cathode materials. The electrochemical tests indicated that the Cd-doped samples exhibited better electrochemical performance than the pristine material; specifically, at a doping amount of 0.01 mol, the initial discharge capacity was 186.3 mAh g−1 with a capacity retention of 87.49% after 200 cycles at a current rate of 0.5 C and a capacity retention of 72.43% after 300 cycles at a current rate of 2 C, whereas the pristine material only had an initial capacity of 173.2 mAh g−1 and a capacity retention of 61.25% and 41.09% for the same current rate and cycle number, respectively. In addition, at 8 C, the discharge capacity was 129.8 mAh g−1 for the Cd-doped samples but only 119.6 mAh g−1 for the pristine material. The enhanced electrochemical performance was attributed to the in situ doping modification during the synthesis process of the precursor. This approach effectively stabilized the crystal structure, improved the electronic conductivity of the material, and reduced the impact of the hydrofluoric acid (HF) on the electrode surface due to the generation of CdF2 during the cycle process.
- Published
- 2019