锂离子电池用无溶剂干法电极的制备及其性能研究

Preparation and characterization of solvent-free dry electrodes for lithium ion batteries

采用无溶剂电极制备技术成功制备了锂离子电池用LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)干法电极片,采用扫描电子显微镜(SEM)和X射线能谱仪(EDS)对干法电极片的形貌和元素分布进行了分析测试,通过倍率充放电、交流阻抗、循环充放电等测试手段研究了干法电极片的电化学性能。结果表明:纤维状PTFE广泛地分布在LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)活性物质颗粒的周围,在干法电极内部形成了一个致密、完整、柔性的网状黏结剂结构;电极循环500圈后,容量保持率为94.89%,循环性能明显优于传统的湿法涂布电极。500圈循环后的电极片内部仍保持着稳定的网状黏结剂结构,LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)活性物质颗粒表面的裂隙显著少于湿法涂布电极,表明由PTFE纤维构成的三维网络结构能够有效地改善电极片的抗劣化性能。由于干法电极技术在制备过程中不使用任何溶剂,有减少原材料、降低能耗、环境友好的优点,且该技术支持制备厚电极进而能够提高锂离子电池的能量密度,具有较强的实际应用价值。

LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) dry electrodes for lithium-ion batteries were prepared using a solvent-free electrode preparation technology.The morphology and elemental distribution of the dry electrodes were analyzed using a scanning electron microscope and an X-ray energy spectrometer(EDS).The electrochemical performance of LiNi0.8Co0.1Mn0.1O2 dry electrodes were characterized by the rate of charge/discharge,electrochemical impedance spectroscopy,and cycle charge/discharge.The results show that in the dry electrodes,PTFE fibers are widely distributed around the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) particles,which form a dense,complete,and flexible net-like binding structure.Batteries containing the dry electrodes delivered an excellent capacity retention of 94.89%for more than 500 cycles,which is much greater than that of traditional wet-coated electrodes.Inside the dry electrodes after 500 cycles,a stable net-like binding structure was maintained,and there were significantly less cracks on the surface of the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) particles than on the wet-coated electrodes.These results indicate that the three-dimensional net-like binding structure formed by PTFE fibers can effectively improve the anti-deterioration performance of the electrodes.No solvents were used in the preparation of the dry electrodes,which can reduce the amount of raw materials and energy consumption,and thus be environmentally friendly.The solvent-free electrode preparation technology provides many practical applications in the preparation of thick electrodes to i ncrease the energy density of lithium-ion batteries.