1. High-Li+-fraction ether-side-chain pyrrolidinium–asymmetric imide ionic liquid electrolyte for high-energy-density Si//Ni-rich layered oxide Li-ion batteries.
- Author
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Umesh, Bharath, Rath, Purna Chandra, Patra, Jagabandhu, Hernandha, Rahmandhika Firdauzha Hary, Majumder, Subhasis Basu, Gao, Xinpei, Bresser, Dominic, Passerini, Stefano, Lai, Hong-Zheng, Chang, Tseng-Lung, and Chang, Jeng-Kuei
- Subjects
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SOLID electrolytes , *LITHIUM-ion batteries , *EXOTHERMIC reactions , *IONIC liquids , *DIFFERENTIAL scanning calorimetry , *CARBONATES - Abstract
[Display omitted] • Ether-chain pyrrolidinium and asymmetric imide enables a high Li+ fraction in IL electrolyte. • This electrolyte is first used for a Si/CNT/G||NCM-811 full cell. • Robust LiF- and Li 3 N-rich SEI has balanced organic/inorganic components is crucial. • The long-existing rate capability problem of IL electrolyte has been overcome. • The electrolyte suppresses the interfacial exothermic reactions of delithiated NCM-811. In this study, Si nanoparticles with interweaving carbon nanotubes are wrapped by graphitic sheets to achieve high conductivity and high dimensional stability of a composite anode (denoted as Si/CNT/G) for Li-ion batteries. In addition, an ionic liquid (IL) electrolyte that consists of ether-side-chain pyrrolidinium, asymmetric imide, and a high Li+ fraction is prepared. This electrolyte is for the first time employed for Si-based Li-ion batteries. Decomposition of the ether groups creates organic components in the solid electrolyte interphase (SEI). The high Li+ concentration promotes decomposition of the (fluorosulfonyl)(trifluoromethanesulfonyl)imide (FTFSI−) anions, leading to a LiF- and Li 3 N-rich SEI. The organic-inorganic balanced SEI is responsible for the excellent charge-discharge properties of the Si/CNT/G anode. The FTFSI− anions exhibit low corrosivity toward the Al current collector and high compatibility with the LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM-811) cathode. With a charging voltage of 4.5 V, remarkable reversible capacities and cycling stability of NCM-811 in the high-Li+-fraction N -methoxyethyl- N -methylpyrrolidinium/FTFSI IL electrolyte are observed. Differential scanning calorimetry is used to examine the interfacial exothermic reactions between the delithiated NCM-811 and various electrolytes. After 300 charge-discharge cycles, the capacity retention of a Si/CNT/G||NCM-811 full cell with the proposed IL electrolyte is 80% with a Coulombic efficiency of ∼99.9%. These values are significantly higher than those of the conventional carbonate electrolyte cell. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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