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Electrochemo‐Mechanical Effects on Structural Integrity of Ni‐Rich Cathodes with Different Microstructures in All Solid‐State Batteries
Author(s) -
Liu Xiangsi,
Zheng Bizhu,
Zhao Jun,
Zhao Weimin,
Liang Ziteng,
Su Yu,
Xie Chenpeng,
Zhou Ke,
Xiang Yuxuan,
Zhu Jianping,
Wang Hongchun,
Zhong Guiming,
Gong Zhengliang,
Huang Jianyu,
Yang Yong
Publication year - 2021
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.202003583
Subject(s) - materials science , crystallite , scanning electron microscope , microstructure , dielectric spectroscopy , composite material , cathode , electrochemistry , chemical engineering , electrode , metallurgy , chemistry , engineering
The electrochemo‐mechanical effects on the structural integrity of electrode materials during cycling is a non‐negligible factor that affects the cyclability and rate performance of all solid‐state batteries (ASSBs). Herein, combined with in situ electrochemical impedance spectroscopy (EIS), focused ion beam (FIB)–scanning electron microscope (SEM), and solid state nuclear magnetic resonance (ssNMR) techniques, the electrochemical performance and electrochemo‐mechanical behavior are compared of conventional polycrystalline NCM811 (LiNi 0.8 Co 0.1 Mn 0.1 O 2 ), small‐size polycrystalline NCM811 and single‐crystal (S‐) NCM811 in Li 10 SnP 2 S 12 based ASSBs during long charge–discharge cycles. The results show that the deteriorating performance of both large and small polycrystalline NCM811 originates from their inherent structural instability at >4.15 V, induced by the visible voids between the randomly oriented grains and microcracks due to the electrode pressing process and severe anisotropic volume change during cycling, rather than lithium ion transport in the primary particle. In contrast, S‐NCM811 with good microstructural integrity show remarkably high capacity (187 mAh g −1 , 18 mA g −1 ), stable cyclability (100 cycles, retention of 64.5%), and exceptional rate capability (102 mAh g −1 at 180 mA g −1 ) in ASSBs even without surface modification. Moreover, 1 wt% LiNbO 3 @S‐NCM811 further demonstrates excellent initial discharge capacity and capacity retention. This work highlights the critical role of electrochemo‐mechanical integrity and offers an promising path towards mechanically‐reliable cathode materials for ASSBs.