3D打印锂离子电池正极的制备及性能

Preparation and performance of 3D-printed positive electrode for lithium-ion battery

采用挤出式3D打印技术制备锂离子电池电极,选取三元镍钴锰酸锂(Li Ni0.5Co0.2Mn0.3O2)作为正极活性材料,以去离子水、羟乙基纤维素和其他添加剂为溶剂来制备性能稳定且适合3D打印技术的锂离子电池正极墨水,利用流变仪、X射线衍射仪、电池测试仪、ANSYS模拟等探究了增稠剂种类和含量、墨水黏度、打印工艺等对墨水流变性质和可打印性能的影响.结果表明:选取羟乙基纤维素/羟丙基纤维素质量比为1∶1混合且质量分数为3%时,所制备的墨水黏度为20.26 Pa·s,此时墨水具有较好的流变性,打印过程出墨均匀,打印电极光滑平整,满足后期墨水的可打印性要求,经模拟分析,墨水黏度对墨水流动性影响明显;电极材料经超声分散、打印、烧结等过程后未造成原有晶体结构的改变;电极首次充放电容量分别为226.5和119.4 mA·h·g-1,经过20次循环后,电池充放电容量的变化率减小并趋于稳定,3D打印电极表现出良好的循环稳定性.

Miniaturized batteries are widely utilized in microscale devices, and 3 D printing technology has great advantages in the manufacture of miniaturized battery electrodes. Lithium–nickel–cobalt–manganate material(LiNi0.5 Co0.2 Mn0.3 O2) is gradually becoming a mainstream cathode material for lithium-ion batteries due to its high energy density, high rate of performance, high stability, and low cost. In this study, we prepared lithium-ion-battery electrodes using extrusion-based three-dimensional(3 D) printing technology, and we selected ternary nickel–cobalt–manganese hydride as the positive active material. Subsequently, using deionized water, hydroxyethyl cellulose, and other additives, positive inks was prepared for the lithium-ion battery that exhibited stable performance and adequate 3 D printing. The effects of thickener type and content, ink viscosity, and the printing process on the rheological properties and printability of the ink were investigated using a rheometer, X-ray diffraction, a battery tester, and ANSYS simulation analysis. The results show that when the mass ratio of hydroxyethyl cellulose/hydroxypropyl cellulose is 1∶1 and the mass fraction is 3%, the viscosity of the prepared ink is 20.26 Pa·s, and it shows good rheology and uniformity in printing. At present, the printing electrode has good rheology, steady ink outflow, and a smooth surface, which satisfies the printability requirements of the ink. Additionally, the simulation results show that the fluidity of the ink is significantly influenced by its viscosity. The electrode preparation process, e.g., ultrasonic dispersion, printing, or sintering, does not lead to a change in the crystal structure of the electrode material. The first-charge and discharge capacities of the electrodes are 226.5 and 119.4 mrespectively.After 20 cycles,the change rates of the charge and discharge capacities in the battery decrease and then tend to become stable.Lastly,the 3D printed electrode exhibits good cycle stability.