Zhengyi Lu,Lin Peng,Yi Rong,Enli Wang,Ruhua Shi,Hongxun Yang,Yadong Xu,Ruizhi Yang,Chao Jin
Poly(ethylene oxide) (PEO) and Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO)-based composite polymer electrolytes (CPEs) are considered one of the most promising solid electrolyte systems. However, agglomeration of LLZTO within PEO and lack of Li + channels result in poor electrochemical properties. Herein, a functional supramolecular combination (CD-TFSI) consisting of active β-cyclodextrin (CD) supramolecular with self-assembled LiTFSI salt is selected as an interface modifier to coat LLZTO fillers. Benefiting from vast H-bonds formed between β-CD and PEO matrix and/or LLZTO, homogeneous dispersion and tight interface contact are obtained. Moreover, 6 Li NMR spectra confirm a new Li + transmission pathway from PEO matrix to LLZTO ceramic then to PEO matrix in the as-prepared PEO/LLZTO@CD-TFSI CPEs due to the typical cavity structure of β-CD. As a proof, the conductivity is increased from 5.3 × 10 −4 S cm −1 to 8.7 × 10 −4 S cm −1 at 60 °C, the Li + transference number is enhanced from 0.38 to 0.48, and the electrochemical stability window is extended to 5.1 V versus Li/Li + . Li‖LiFePO 4 CR2032 coin full cells and pouch cells prove the practical application of the as-prepared PEO/LLZTO@CD-TFSI CPEs. This work offers a new strategy of interface modifying LLZTO fillers with functional supramolecular combination to optimize PEO/LLZTO CPEs for solid lithium batteries.
Yipeng Yang,Yanting Ma,Kaineng Feng,Songsheng Zheng,Zhaolin Wang
Semi-solid electrolytes tend to inherit the advantages of both solid-state electrolytes and liquid electrolytes. However, the challenge is to simultaneously enhance both ionic conductivity, transference number and long cycle performance of batteries. In this study, a semi-solid electrolyte was successfully synthesized with a hollow structured metal organic framework (HMOF) and a polymer binder (PVDF). The hollow structure of HMOF serves as a framework to encapsulate a large amount of lithium salt and electrolyte, reducing concentration polarization in lithium metal batteries. Its unique pore structure and abundant hydroxyl functional groups can restrict anion movement, thereby increasing the Li-ion transference number. On the other hand, the PVDF acts as a binder, making the electrolyte thinner, more flexible, and easier to process for broader applications. Furthermore, a Li@HMOF semi-solid electrolyte (LHMSSE) was fabricated by adding Bis (trifluoromethane) sulfonimide lithium salt (LiTFSI) into the HMOF(Li@HMOF), which exhibits a high ionic conductivity of 0.89 mS cm −1 at 30 °C and a high Li-ion transference number of 0.75 at 30 °C. Notably, the Lithium symmetric battery of Li||LHMSSE ||Li can operate stably for over 1200 h at a current density of 0.2 mA cm −2 , and the lithium metal full battery of Li||LHMSSE||LFP (LiFePO 4 ) retains a capacity of 127.7 mAh g −1 after 2000 cycles at 1C, with a capacity retention rate of 89.1 % and an average coulombic efficiency of 99.9 %. When paired with high-load LFP (10 mg cm −2 ) or NCM811 (LiNi 0.8 Co 0.1 Mn 0.1 O 2 ) (10 mg cm −2 ) cathodes, a stable cycling performance can be achieved at a rate of 0.2C.
Ning Zhou,Yufeng Wang,Yang Zhou,Jinyou Shen,Yong Zhou,Yong Yang
Star-shaped polymeric ionic liquids (PIL-3 and PIL-4) based on poly(2-(dimethyl-ethyl-amino)ethyl methacrylate) bis(trifluoromethylsulfonyl)imide (P(EtDMAEMA-TFSI)) with three-arm and four-arm architectures were prepared through atom transfer radical polymerization (ATRP) and ion exchange. Subsequently, gel polymer electrolytes (GPEs) comprising PIL host, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl)imide (DEME-TFSI) ionic liquid (IL) plasticizer with the same anion unit and LiTFSI salt were obtained. Compared with the linear PIL possessing the same elements, the increase of branches for PIL decreases the crystallity and glass transition temperature (T g ) of the corresponding GPEs. Accordingly, the ionic conductivity , electrochemical window and ion transport number of three-arm and four-arm PILs based GPEs (PIL-GPE-3 and PIL-GPE-4) are obviously superior to the linear contrastive sample. Among lithium metal batteries assembled by linear, three-arm and four-arm PILs based GPEs, Li/PIL-GPE-4/LiFePO 4 presents the best performance. The specific discharge capacity attains 151 mAh g −1 at 0.1 C, the capacity retention ratio achieves 93.6% after 100 cycles at 60 °C, and the coulombic efficiency is around 99%. The outstanding compatibility between PIL-4 and IL and the resulted interfacial stability between PIL-GPE-4 and electrodes both contribute to the excellent performance.
危险品化学品经营许可证（带存储）