A tough Janus-faced CEI film for high voltage layered oxide cathodes beyond 4.6 V

Qin, Yinping; Cheng, Hongyu; Zhou, Jingjing; Li, Meng; Ding, Xiaoliang; Li, Yuanhang; Huang, Yijia; Chen, Zhenlian; Shen, Cai; Wang, Deyu; Liu, Yang; Guo, Bingkun

doi:10.1016/j.ensm.2023.02.022

“…Meanwhile, as shown in Figure 4c, d, the variations of the lattice parameters and volume for HE‐WD are reduced after any cycles, compared with that of NCM‐811. The variation of 003 peak is a significant signal for structure changes [54] and the shifts of the 003 peak at corresponding cut‐off voltages (Figure 4e) and cycles (Figure 4f) show the smaller structure changes of HE‐WD than that of NCM‐811. The analyses from XRD measurements indicate the superior high structure stability of HE‐WD when cycled at high voltage.…”

Section: Resultsmentioning

confidence: 99%

“…[53] Meanwhile, as shown in Figure 4c, d, the variations of the lattice parameters and volume for HE-WD are reduced after any cycles, compared with that of NCM-811. The variation of 003 peak is a significant signal for structure changes [54] and the shifts of the 003 peak at corresponding cut-off voltages (Figure 4e To further study the stabilization effect of high-entropy doping, the charge-transfer resistance (R ct ) of electrochemical impedance spectroscopy (EIS) measurements is applied during a single charge-discharge cycle (Ex situ EIS, Figure S6a, b) and after different cycles (Figure S6c, d). The structure changes of the cathodes can be characterized through R ct according to the previous researches.…”

Section: Resultsmentioning

confidence: 99%

Low‐Electronegativity Cationic High‐Entropy Doping to Trigger Stable Anion Redox Activity for High‐Ni Co‐Free Layered Cathodes in Li‐Ion Batteries

Liang,

Qi,

Chen

et al. 2024

Angewandte Chemie

1

0

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LiNi0.8Co0.1Mn0.1O2 (NCM‐811) exhibits the highest capacity in commercial lithium‐ion batteries (LIBs), and the high Ni content (80%) provides the only route for high energy density. However, the cationic structure instability arisen from the increase of Ni content (>80%) limits the further increase of the capacity, and inevitable O2 release related to anionic structure instability hinders the utilization of anion redox activity. Here, by comparing various combinations of high‐entropy dopants substituted Co element, we propose a low‐electronegativity cationic high‐entropy doping strategy to fabricate the high‐Ni Co‐free layered cathode (LiNi0.8Mn0.12Al0.02Ti0.02Cr0.02Fe0.02O2) that exhibits much higher capacity and cycling stability. Configurational disorder originated from cationic high‐entropy doping in transition metal (TM) layer, anchors the oxidized lattice oxygen ((O2)n‐) to preserve high (O2)n‐ content, triggering the anion redox activity. Electron transfer induced by applying TM dopants with lower electronegativity than that of Co element, increases the electron density of O in TM‐O octahedron (TM‐O6) configuration to reach higher (O2)n‐ content, resulting in the higher anion redox activity. With exploring the stabilization effect on both cations and anions of high‐entropy doping and low‐electronegativity cationic modified anion redox activity, we propose an innovative and variable pathway for rationally tuning the properties of commercial cathodes.

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“…[53] Meanwhile, as shown in Figure 4c, d, the variations of the lattice parameters and volume for HE-WD are reduced after any cycles, compared with that of NCM-811. The variation of 003 peak is a significant signal for structure changes [54] and the shifts of the 003 peak at corresponding cut-off voltages (Figure 4e…”

Section: Resultsmentioning

confidence: 99%

Low‐Electronegativity Cationic High‐Entropy Doping to Trigger Stable Anion Redox Activity for High‐Ni Co‐Free Layered Cathodes in Li‐Ion Batteries

Liang,

Qi,

Chen

et al. 2024

View full text Add to dashboard Cite

LiNi0.8Co0.1Mn0.1O2 (NCM‐811) exhibits the highest capacity in commercial lithium‐ion batteries (LIBs), and the high Ni content (80%) provides the only route for high energy density. However, the cationic structure instability arisen from the increase of Ni content (>80%) limits the further increase of the capacity, and inevitable O2 release related to anionic structure instability hinders the utilization of anion redox activity. Here, by comparing various combinations of high‐entropy dopants substituted Co element, we propose a low‐electronegativity cationic high‐entropy doping strategy to fabricate the high‐Ni Co‐free layered cathode (LiNi0.8Mn0.12Al0.02Ti0.02Cr0.02Fe0.02O2) that exhibits much higher capacity and cycling stability. Configurational disorder originated from cationic high‐entropy doping in transition metal (TM) layer, anchors the oxidized lattice oxygen ((O2)n‐) to preserve high (O2)n‐ content, triggering the anion redox activity. Electron transfer induced by applying TM dopants with lower electronegativity than that of Co element, increases the electron density of O in TM‐O octahedron (TM‐O6) configuration to reach higher (O2)n‐ content, resulting in the higher anion redox activity. With exploring the stabilization effect on both cations and anions of high‐entropy doping and low‐electronegativity cationic modified anion redox activity, we propose an innovative and variable pathway for rationally tuning the properties of commercial cathodes.

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“…We further anticipate that the presence of excessive free SN molecules with high polarity may induce CEI dissolution during repeated cycles, albeit it may beneficially enable N-rich interphase. [22,26] We therefore utilize the balancing co-solvent, DEC, with a relatively low dielectric constant to tune the solvation structure of the electrolyte and to ensure low solvating capability for the interphase components. To demonstrate this principle, we prepared the following three electrolytes.…”

Section: The Electrolyte Design Principlementioning

confidence: 99%

Electrolyte Engineering with Tamed Electrode Interphases for High‐Voltage Sodium‐Ion Batteries

Liu,

Zhu,

Wang

et al. 2024

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Sodium‐ion batteries (SIBs) hold great promise for next‐generation grid‐scale energy storage. However, the highly instable electrolyte/electrode interphases threat long‐term cycling of high‐energy SIBs. In particular, the instable cathode electrolyte interphase (CEI) at high voltage causes persistent electrolyte decomposition, transition metal dissolution and fast capacity fade. Here we propose a balanced principle for molecular design of SIB electrolytes that enable an ultra‐thin, homogeneous and robust CEI layer by coupling an intrinsically oxidation stable succinonitrile solvent with moderately solvating carbonates. The proposed electrolyte not only shows limited anodic decomposition thus leading to a thin CEI, but also suppresses dissolution of CEI components at high voltage. Consequently, the tamed electrolyte/electrode interphases enable extremely stable cycling of Na3V2O2(PO4)2F (NVOPF) cathodes with outstanding capacity retention (> 90%) over 3000 cycles (eight months) at 1 C with a high charging voltage of 4.3 V. Further, the NVOPF||hard carbon full cell shows stable cycling over 500 cycles at 1 C with a high average Coulombic efficiency of 99.6%. The electrolyte also endows high‐voltage operation of SIBs with great temperature adaptability from −25 oC to 60 °C, shedding light on the essence of fundamental electrolyte design for SIBs operating under harsh conditions.This article is protected by copyright. All rights reserved

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A tough Janus-faced CEI film for high voltage layered oxide cathodes beyond 4.6 V

Cited by 22 publications

References 34 publications

Low‐Electronegativity Cationic High‐Entropy Doping to Trigger Stable Anion Redox Activity for High‐Ni Co‐Free Layered Cathodes in Li‐Ion Batteries

Low‐Electronegativity Cationic High‐Entropy Doping to Trigger Stable Anion Redox Activity for High‐Ni Co‐Free Layered Cathodes in Li‐Ion Batteries

Low‐Electronegativity Cationic High‐Entropy Doping to Trigger Stable Anion Redox Activity for High‐Ni Co‐Free Layered Cathodes in Li‐Ion Batteries

Electrolyte Engineering with Tamed Electrode Interphases for High‐Voltage Sodium‐Ion Batteries

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