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Manipulating External Electric Field and Tensile Strain toward High Energy Density Stability in Fast-Charging Li-Rich Cathode Materials
journal contribution
posted on 2020-03-09, 19:37 authored by Pengfei Liu, Wei He, Yong Cheng, Qian Wang, Chenying Zhang, Qingshui Xie, Jiangtao Han, Zhensong Qiao, Hongfei Zheng, Qun Liu, Laisen Wang, Baihua Qu, Qing Luo, Zi-Zhong Zhu, Dong-Liang PengLi-rich
layered oxides (LLOs) are promising cathodes for lithium-ion
batteries because of their high energy density provided by anionic
redox. Although great improvements have been achieved in electrochemical
performance, little attention has been paid to the energy density
stability during fast charging. Indeed, LLOs have severe capacity
fading and voltage decay especially at a high state of charge (SOC),
disabling the application of the frequently used constant-current–constant-voltage
mode for fast charging. Herein, we address this problem by manipulating
the external electric field and tensile strain induced by lattice
expansion effect in nanomaterials under the guidance of theoretical
calculations, which indicate that LLOs at high SOC have almost a zero
band gap and a low oxygen formation energy. This strategy will weaken
polarization, stabilize lattice oxygen, and restrict phase transition
simultaneously. Thus, the energy density during fast charging can
be highly stabilized. Therefore, it may be of great value for the
practical application of layered cathodes.