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201 results on '"Qian, Yumin"'

15. Electronegativity‐Induced Single‐Ion Conducting Polymer Electrolyte for Solid‐State Lithium Batteries.

Author

Hou, Tianyi, Qian, Yumin, Li, Dinggen, Xu, Bo, Huang, Zhenyu, Liu, Xueting, Wang, Haonan, Jiang, Bowen, Xu, Henghui, and Huang, Yunhui

Subjects
POLYELECTROLYTES, SOLID electrolytes, CONDUCTING polymers, LITHIUM cells, IONIC conductivity
Abstract

The application of solid polymer electrolytes (SPEs) is severely impeded by the insufficient ionic conductivity and low Li+ transference numbers (tLi+). Here, we report an iodine‐driven strategy to address both the two long‐standing issues of SPEs simultaneously. Electronegative iodine‐containing groups introduced on polymer chains effectively attract Li+ ions, facilitate Li+ transport, and promote the dissociation of Li salts. Meanwhile, iodine is also favorable to alleviate the strong O−Li+ coordination through a Lewis acid–base interaction, further improving the ionic conductivity and tLi+. As a proof of concept, an iodinated single‐ion conducting polymer electrolyte (IPE) demonstrates a high ionic conductivity of 0.93 mS cm−1 and a high tLi+ of 0.86 at 25 °C, which is among the best results ever reported for SPEs. Moreover, symmetric Li/Li cells with IPE achieve a long‐term stability over 2600 h through the in‐situ formed LiF‐rich interphase. As a result, Li−S battery with IPE maintains a high capacity of 623.7 mAh g−1 over 300 cycles with an average Coulombic efficiency of 99%. When matched with intercalation cathode chemistries, Li/IPE/LiFePO4 and Li/IPE/LiNi0.8Mn0.1Co0.1O2 solid‐state batteries also deliver high‐capacity retentions of 95% and 97% at 0.2 C after 120 cycles, respectively. [ABSTRACT FROM AUTHOR]

Published
2023
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22. Multifunctional Active-Center-Transferable Platinum/Lithium Cobalt Oxide Heterostructured Electrocatalysts towards Superior Water Splitting

Author

Zheng, Xiaobo, Cui, Peixin, Qian, Yumin, Zhao, Guoqiang, Zheng, Xusheng, Xu, Xun, Cheng, Zhenxiang, Liu, Yuanyue, Dou, Shi Xue, Sun, Wenping, Zheng, Xiaobo, Cui, Peixin, Qian, Yumin, Zhao, Guoqiang, Zheng, Xusheng, Xu, Xun, Cheng, Zhenxiang, Liu, Yuanyue, Dou, Shi Xue, and Sun, Wenping

Abstract

© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Designing cost-effective and efficient electrocatalysts plays a pivotal role in advancing the development of electrochemical water splitting for hydrogen generation. Herein, multifunctional active-center-transferable heterostructured electrocatalysts, platinum/lithium cobalt oxide (Pt/LiCoO2) composites with Pt nanoparticles (Pt NPs) anchored on LiCoO2 nanosheets, are designed towards highly efficient water splitting. In this electrocatalyst system, the active center can be alternatively switched between Pt species and LiCoO2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Specifically, Pt species are the active centers and LiCoO2 acts as the co-catalyst for HER, whereas the active center transfers to LiCoO2 and Pt turns into the co-catalyst for OER. The unique architecture of Pt/LiCoO2 heterostructure provides abundant interfaces with favorable electronic structure and coordination environment towards optimal adsorption behavior of reaction intermediates. The 30 % Pt/LiCoO2 heterostructured electrocatalyst delivers low overpotentials of 61 and 285 mV to achieve 10 mA cm−2 for HER and OER in alkaline medium, respectively.

Published
2020

30. O-coordinated W-Mo dual-atom catalyst for pH-universal electrocatalytic hydrogen evolution

Author

Yang, Yang, primary, Qian, Yumin, additional, Li, Haijing, additional, Zhang, Zhenhua, additional, Mu, Yuewen, additional, Do, David, additional, Zhou, Bo, additional, Dong, Jing, additional, Yan, Wenjun, additional, Qin, Yong, additional, Fang, Li, additional, Feng, Renfei, additional, Zhou, Jigang, additional, Zhang, Peng, additional, Dong, Juncai, additional, Yu, Guihua, additional, Liu, Yuanyue, additional, Zhang, Xianming, additional, and Fan, Xiujun, additional

Published
2020
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36. Reversible anionic redox chemistry in layered Li4/7[□1/7Mn6/7]O2enabled by stable Li–O-vacancy configuration

Author

Cao, Xin, Li, Haifeng, Qiao, Yu, He, Ping, Qian, Yumin, Yue, Xiyan, Jia, Min, Cabana, Jordi, and Zhou, Haoshen

Abstract

The combination of anionic and cationic activities within Li-rich materials breaks through the traditional capacity limitation and achieves high-energy-density batteries. However, the utilization of anionic oxygen redox reactions always leads to detrimental lattice oxygen release, which accelerates structural distortion and electrochemical performance deterioration. In contrast to the typical Li–O–Li configuration in Li-rich layered oxides, not only can oxygen redox behaviors be triggered within layered Li4/7[□1/7Mn6/7]O2(□: Mn vacancy) with Li–O-vacancy configuration, but lattice oxygen loss can be effectively suppressed. Upon Li+(de)intercalations, Mn vacancy within the TM layer also enables reversible structural evolution and Li migration processes, further boosting high output capacity and long-term cycling stability. Besides, not only can the irreversible/reversible anionic/cationic redox reactions be clearly unraveled, but their capacity distributions can be roughly quantified upon cycling. Overall, our findings demonstrate that the introduction of Mn vacancy provides a promising configuration to achieve high-capacity cathode candidates for next-generation Li-ion batteries.

Published
2022
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46. Gel‐Derived Amorphous Bismuth–Nickel Alloy Promotes Electrocatalytic Nitrogen Fixation via Optimizing Nitrogen Adsorption and Activation.

Author

Fang, Zhiwei, Wu, Ping, Qian, Yumin, and Yu, Guihua

Subjects
AMORPHOUS alloys, NITROGEN fixation, ADSORPTION (Chemistry), CATALYTIC activity, CHARGE exchange, STEAM reforming, BISMUTH
Abstract

To achieve the electrochemical nitrogen reduction reaction (NRR) for efficient and sustainable NH3 production, catalysts should exhibit high selectivity and activity with optimal adsorption energy. Herein we developed a three‐dimensional (3D) amorphous BiNi alloy toward a significantly enhanced NRR compared with its crystalline and metal counterparts. Ni alloying enables the chemisorption of nitrogen and the lower free‐energy change for the *NNH formation, and the 3D alloy electrocatalyst exhibits high catalytic activity for NH3 production with a yield rate of 17.5 μg h−1 mgcat−1 and Faradaic efficiency of 13.8 %. The enhanced electron transfer and increased electrochemical surface area were revealed in the interconnected porous scaffold, affording it sufficiently efficient and stable activity for potential practical applications. This work offers new insights into optimizing the adsorption energy of reactants and intermediates combined with tuning the crystallinity of NRR electrocatalysts. [ABSTRACT FROM AUTHOR]

Published
2021
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49. Enhanced Surface Interactions Enable Fast Li+ Conduction in Oxide/Polymer Composite Electrolyte.

Author

Wu, Nan, Chien, Po‐Hsiu, Qian, Yumin, Li, Yutao, Xu, Henghui, Grundish, Nicholas S., Xu, Biyi, Jin, Haibo, Hu, Yan‐Yan, Yu, Guihua, and Goodenough, John B.

Subjects
POLYELECTROLYTES, SURFACE interactions, OXIDE ceramics, INTERFACIAL resistance, OXIDES
Abstract

Li+‐conducting oxides are considered better ceramic fillers than Li+‐insulating oxides for improving Li+ conductivity in composite polymer electrolytes owing to their ability to conduct Li+ through the ceramic oxide as well as across the oxide/polymer interface. Here we use two Li+‐insulating oxides (fluorite Gd0.1Ce0.9O1.95 and perovskite La0.8Sr0.2Ga0.8Mg0.2O2.55) with a high concentration of oxygen vacancies to demonstrate two oxide/poly(ethylene oxide) (PEO)‐based polymer composite electrolytes, each with a Li+ conductivity above 10−4 S cm−1 at 30 °C. Li solid‐state NMR results show an increase in Li+ ions (>10 %) occupying the more mobile A2 environment in the composite electrolytes. This increase in A2‐site occupancy originates from the strong interaction between the O2− of Li‐salt anion and the surface oxygen vacancies of each oxide and contributes to the more facile Li+ transport. All‐solid‐state Li‐metal cells with these composite electrolytes demonstrate a small interfacial resistance with good cycling performance at 35 °C. [ABSTRACT FROM AUTHOR]

Published
2020
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