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Impact of Structural Transformation on Electrochemical Performances of Li-Rich Cathode Materials: The Case of Li2RuO3
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2019-05-24 , DOI: 10.1021/acs.jpcc.9b02887 Feng Zheng , Shiyao Zheng , Peng Zhang 1 , Xiaofeng Zhang , Shunqing Wu , Yong Yang , Zi-zhong Zhu
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2019-05-24 , DOI: 10.1021/acs.jpcc.9b02887 Feng Zheng , Shiyao Zheng , Peng Zhang 1 , Xiaofeng Zhang , Shunqing Wu , Yong Yang , Zi-zhong Zhu
Affiliation
Exploration of Li-rich transition-metal (TM) oxides with active anionic redox reaction has paved a promising way for the design of high-capacity Li-ion battery cathode materials. In the present work, we show that our predicted two-step structural transformation and resulted structural evolution for Li2RuO3 agree well with our experiments. The anionic oxidation occurs upon delithiation, and the reduction of structural stability would initiate cation migration from Li–Ru layers to adjacent Li layers, which can in turn restabilize the delithiated structures and suppress the oxygen evolution, providing a good explanation on the observed high reversible capacity. However, the gradual migration of cations will cause a serious voltage decay of Li2RuO3 upon cycling, as well as poor cycling kinetics because of the fact that migrating cations in Li layers impede the Li diffusion. Our finding significantly broadens the current understanding on the electrochemistry of Li2RuO3 and provides important guidelines for the future design of Li-rich TM oxides as high-capacity cathode materials.
中文翻译:
结构转变对富锂正极材料电化学性能的影响:以Li2RuO3为例
通过活性阴离子氧化还原反应探索富含锂的过渡金属(TM)氧化物,为设计高容量锂离子电池正极材料铺平了一条有希望的途径。在目前的工作中,我们表明,我们预测的Li 2 RuO 3的两步结构转变和所导致的结构演变与我们的实验吻合良好。阴离子氧化在去锂化时发生,并且结构稳定性的降低会引发阳离子从Li-Ru层迁移到相邻的Li层,进而可以使去锂化的结构再稳定化并抑制氧的释放,从而为观察到的高可逆性提供了一个很好的解释容量。然而,阳离子的逐渐迁移将导致Li 2 RuO 3的严重电压衰减。由于在Li层中迁移的阳离子会阻碍Li的扩散,因此循环时的循环动力学以及较差的循环动力学。我们的发现大大拓宽了当前对Li 2 RuO 3电化学的理解,并为将来设计富锂TM氧化物作为高容量阴极材料提供了重要指导。
更新日期:2019-05-24
中文翻译:
结构转变对富锂正极材料电化学性能的影响:以Li2RuO3为例
通过活性阴离子氧化还原反应探索富含锂的过渡金属(TM)氧化物,为设计高容量锂离子电池正极材料铺平了一条有希望的途径。在目前的工作中,我们表明,我们预测的Li 2 RuO 3的两步结构转变和所导致的结构演变与我们的实验吻合良好。阴离子氧化在去锂化时发生,并且结构稳定性的降低会引发阳离子从Li-Ru层迁移到相邻的Li层,进而可以使去锂化的结构再稳定化并抑制氧的释放,从而为观察到的高可逆性提供了一个很好的解释容量。然而,阳离子的逐渐迁移将导致Li 2 RuO 3的严重电压衰减。由于在Li层中迁移的阳离子会阻碍Li的扩散,因此循环时的循环动力学以及较差的循环动力学。我们的发现大大拓宽了当前对Li 2 RuO 3电化学的理解,并为将来设计富锂TM氧化物作为高容量阴极材料提供了重要指导。