Mereacre Valeriu, Stüble Pirmin, Ghamlouche Ahmad, Binder Joachim R
Institute for Applied Materials, Energy Storage Systems, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany.
Helmholtz Institute Ulm, D-89081 Ulm, Germany.
Nanomaterials (Basel). 2021 Feb 22;11(2):548. doi: 10.3390/nano11020548.
LiNbO-coated LiNiMnO spinel was fabricated by two methods: using hydrogen-peroxide as activating agent and sol-gel method. The structure of the obtained cathode materials was investigated using a scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and the electrochemical properties of the prepared cathodes were probed by charge-discharge studies. The morphology of the coating material on the surface and the degree of coverage of the coated particles were investigated by SEM, which showed that the surface of LiNiMnO particles is uniformly encapsulated by lithium innovate coating. The influence of the LiNbO coating layer on the spinel's properties was explored, including its effect on the crystal structure and electrochemical performance. XRD studies of the obtained coated active materials revealed very small expansion or contraction of the unit cell. From the capacity retention tests a significant improvement of the electrochemical properties resulted when a novel chemically activated coating process was used. Poorer results, however, were obtained using the sol-gel method. The results also revealed that the coated materials by the new method exhibit enhanced reversibility and stability compared to the pristine and reference ones. It was shown that the morphology of the coating material and possible improvement of communication between the substrates play an important role.
采用两种方法制备了LiNbO包覆的LiNiMnO尖晶石：以过氧化氢为活化剂的方法和溶胶-凝胶法。使用扫描电子显微镜（SEM）、X射线衍射（XRD）、X射线光电子能谱（XPS）对所得阴极材料的结构进行了研究，并通过充放电研究探究了所制备阴极的电化学性能。通过SEM研究了表面包覆材料的形貌以及包覆颗粒的覆盖程度，结果表明LiNiMnO颗粒表面被锂铌酸盐涂层均匀包覆。探讨了LiNbO涂层对尖晶石性能的影响，包括其对晶体结构和电化学性能的影响。对所得包覆活性材料的XRD研究表明，晶胞有非常小的膨胀或收缩。通过容量保持测试发现，采用新型化学活化涂层工艺时，电化学性能有显著改善。然而，使用溶胶-凝胶法得到的结果较差。结果还表明，与原始材料和参比材料相比，采用新方法制备的包覆材料具有更高的可逆性和稳定性。结果表明，包覆材料的形貌以及基体之间可能改善的连通性起着重要作用。
