Wang Lifan, Wang Rui, Wang Jingyue, Xu Rui, Wang Xindong, Zhan Chun
Department of Physical Chemistry, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
ACS Appl Mater Interfaces. 2021 Feb 24;13(7):8324-8336. doi: 10.1021/acsami.0c20100. Epub 2021 Feb 12.
To satisfy the increasing energy density requirements for electric vehicles and grid-scale energy storage systems, Ni-rich layered oxide cathode materials are often fabricated as micron-sized secondary spherical particles consisting of nanosized single crystals. Unfortunately, the hierarchical structure inevitably induces intergranular cracks and parasitic reactions at the cathode-electrolyte interphase, aggravating chemomechanical instability and seriously hindering their practical application. Here, we propose a nanowelding strategy to build consolidation points at the grain boundary of the primary particles, which dramatically enhances the capacity retention and chemomechanical stability. Meanwhile, the oxygen vacancies in the ceria-based solid electrolyte possessing oxygen adsorbing and storage capability can restrain the active oxygenates in the surficial lattice to avoid oxygen evolution. Experimental characterization further confirms that this unique architecture can effectively prevent the liquid electrolyte from penetrating into the active material along the grain boundary and consequently eliminate the adverse effects, including intergranular cracks, cathode electrolyte interface formation and growth, and the layered structure-rock salt phase irreversible transition. This finding provides a promising approach to realize the rapid commercialization of highly stabilized nickel-rich cathode materials for high-performance lithium-ion batteries.
为满足电动汽车和电网规模储能系统不断增长的能量密度要求，富镍层状氧化物阴极材料通常被制备成由纳米级单晶组成的微米级二次球形颗粒。不幸的是，这种层级结构不可避免地会在阴极-电解质界面处引发晶间裂纹和寄生反应，加剧化学机械不稳定性，并严重阻碍其实际应用。在此，我们提出一种纳米焊接策略，在一次颗粒的晶界处构建固结点，这显著提高了容量保持率和化学机械稳定性。同时，具有氧吸附和存储能力的基于二氧化铈的固体电解质中的氧空位可以抑制表面晶格中的活性含氧化合物，以避免析氧。实验表征进一步证实，这种独特的结构可以有效防止液体电解质沿晶界渗透到活性材料中，从而消除包括晶间裂纹、阴极电解质界面形成和生长以及层状结构-岩盐相不可逆转变等不利影响。这一发现为实现用于高性能锂离子电池的高度稳定的富镍阴极材料的快速商业化提供了一种有前景的方法。
