Polyether-b-Amide Based Solid Electrolytes with Well-Adhered Interface and Fast Kinetics for Ultralow Temperature Solid-State Lithium Metal Batteries |
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Authors: | Xueyan Huang Sheng Huang Tianyi Wang Lei Zhong Dongmei Han Min Xiao Shuanjin Wang Yuezhong Meng |
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Affiliation: | 1. The Key Laboratory of Low-carbon Chemistry & Energy Conservation of Guangdong Province/State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou, 510275 P. R. China;2. School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082 P. R. China |
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Abstract: | Solid-state lithium metal batteries (SSLMBs) are highly desirable for energy storage because of the urgent need for higher energy density and safer batteries. However, it remains a critical challenge for stable cycling of SSLMBs at low temperature. Here, a highly viscoelastic polyether-b-amide (PEO-b-PA) based composite solid-state electrolyte is proposed through a one-pot melt processing without solvent to address this key process. By adjusting the molar ratio of PEO-b-PA to lithium bis(trifluoromethanesulphonyl)imide (ethylene oxide:Li = 6:1) and adding 20 wt.% succinonitrile, fast Li+ transport channel is conducted within the homogeneous polymer electrolyte, which enables its application at ultra-low temperature (−20 to 25 °C). The composite solid-state electrolyte utilizes dynamic hydrogen-bonding domains and ion-conducting domains to achieve a low interfacial charge transfer resistance (<600 Ω) at −20 °C and high ionic conductivity (25 °C, 3.7 × 10−4 S cm−1). As a result, the LiFePO4|Li battery based on composite electrolyte exhibits outstanding electrochemical performance with 81.5% capacity retention after 1200 cycles at −20 °C and high discharge specific capacities of 141.1 mAh g−1 with high loading (16.1 mg cm−2) at 25 °C. Moreover, the solid-state SNCM811|Li cell achieves excellent safety performance under nail penetration test, showing great promise for practical application. |
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Keywords: | interfaces low temperature polyether-b-amide solid-state lithium metal  batteries solid-state polymer electrolytes |
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