Lee Sanghan, Jin Wooyoung, Kim Su Hwan, Joo Se Hun, Nam Gyutae, Oh Pilgun, Kim Young-Ki, Kwak Sang Kyu, Cho Jaephil
Department of Energy Engineering and School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
Department of Graphic Arts Information Engineering, Pukyong National University, Busan, 48547, Republic of Korea.
Angew Chem Int Ed Engl. 2019 Jul 29;58(31):10478-10485. doi: 10.1002/anie.201904469. Epub 2019 Jun 24.
Oxygen vacancies (OV) are native defects in transition metal (TM) oxides and their presence has a critical effect on the physicochemical properties of the oxide. Metal oxides are commonly used in lithium-ion battery (LIB) cathodes and there is still a lack of understanding of the role of OVs in LIB research field. Here, we report on the behavior of OVs in a single-crystal LIB cathode during the non-equilibrium states of charge and discharge. We found that microcrack evolution in a single crystal occurs due to OV condensation in specific crystallographic orientations generated by the continuous migration of OVs and TM ions. Moreover, understanding the effects of the presence and diffusion of OVs in metal oxides enables the elucidation of most of the conventional mechanisms of capacity fading in LIBs and provides new insights for new electrochemical applications.
氧空位（OV）是过渡金属（TM）氧化物中的固有缺陷，其存在对氧化物的物理化学性质有至关重要的影响。金属氧化物常用于锂离子电池（LIB）的阴极，在LIB研究领域中，人们对OV的作用仍缺乏了解。在此，我们报告了单晶LIB阴极在非平衡充放电状态下OV的行为。我们发现，由于OV和TM离子的持续迁移在特定晶体取向产生的OV凝聚，单晶中会发生微裂纹演变。此外，了解OV在金属氧化物中的存在和扩散效应，有助于阐明LIB中容量衰减的大多数传统机制，并为新的电化学应用提供新的见解。
