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Influencing Factors on Li-ion Conductivity and Interfacial Stability of Solid Polymer Electrolytes,Exampled by Polycarbonates,Polyoxalates and Polymalonates |
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| Authors: | Dr Xiaoxin Xie Prof Zhaoxu Wang Dr Shuang He Kejun Chen Qiu Huang Peng Zhang Prof Shu-Meng Hao Dr Jiantao Wang Prof Weidong Zhou |
| Institution: | 1. Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029 China
Contribution: Data curation (lead), ?Investigation (lead), Writing - original draft (lead);2. Key Laboratory of Theoretical Organic Chemistry and Functional Molecule of Ministry of Education, Hunan University of Science and Technology, Hunan, 411201 China Contribution: Data curation (equal), ?Investigation (supporting), Software (equal);3. Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029 China Contribution: ?Investigation (supporting), Software (supporting);4. Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029 China Contribution: ?Investigation (supporting);5. Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029 China Contribution: Supervision (supporting);6. China Automotive Battery Research Institute Co., Ltd., Beijing, 101407 China Contribution: Supervision (supporting);7. Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029 China |
| Abstract: | The application of solid polymer electrolytes (SPEs) in all-solid-state(ASS) batteries is hindered by lower Li+-conductivity and narrower electrochemical window. Here, three families of ester-based F-modified SPEs of poly-carbonate (PCE), poly-oxalate (POE) and poly-malonate (PME) were investigated. The Li+-conductivity of these SPEs prepared from pentanediol are all higher than the counterparts made of butanediol, owing to the enhanced asymmetry and flexibility. Because of stronger chelating coordination with Li+, the Li+-conductivity of PME and POE is around 10 and 5 times of PCE. The trifluoroacetyl-units are observed more effective than ?O?CH2?CF2?CF2?CH2?O? during the in situ passivation of Li-metal. Using trifluoroacetyl terminated POE and PCE as SPE, the interfaces with Li-metal and high-voltage-cathode are stabilized simultaneously, endowing stable cycling of ASS Li/LiNi0.6Co0.2Mn0.2O2 (NCM622) cells. Owing to an enol isomerization of malonate, the cycling stability of Li/PME/NCM622 is deteriorated, which is recovered with the introduce of dimethyl-group in malonate and the suppression of enol isomerization. The coordinating capability with Li+, molecular asymmetry and existing modes of elemental F, are all critical for the molecular design of SPEs. |
| Keywords: | All-Solid-State Battery High Voltage Cathode Interfacial Stability Lithium Metal Anode Solid Polymer Electrolyte |