No abstract

Polymerized ionic liquids (PILs) have several advantages over ionic liquids, such as easy handling, good electrochemical performance, and chemical compatibility. In this research, a solid-state electrolyte composite membrane was successfully fabricated by using an imidazolium-based polymerized ionic liquid as polymer matrix, a kind of porous fiber cloth as rigid frame, and lithium bis­(trifluoro­methane­sulfonyl)­imide (LiTFSI) as lithium salt. The ionic conductivity of the composite electrolyte with 2.0 mol/kg LiTFSI is 7.78 × 10–5 S cm–1 at 30 °C and reaches 5.92 × 10–4 S cm–1 at 60 °C, which is considered a satisfactory value for potential application in lithium-ion batteries. The specific discharge capacity of the LiFe­PO4/Li cell with as-prepared composite electrolyte is 138.4 mAh g–1, and 90% of the discharge capacity is retained after 250 cycles at 60 °C. In order to further improve the conductivity, Li1.3­Al0.3­Ti1.7­(PO4)3 (LATP) ceramic electrolyte particles are dispersed in a PIL polymer matrix to prepare the PIL-LiTFSI-LATP composite electrolyte. LiFe­PO4/Li cells using PIL-LiTFSI-LATP (10 wt % LATP) as a solid-state electrolyte exhibit excellent rate performance and high capacity retention (close to 97% after 250 cycles at 60 °C). This work may provide a unique way to prepare a new series of electrolytes for high-performance solid-state lithium batteries.

No abstract

Hard X-ray sources from femtosecond (fs) laser-produced plasmas, including the betatron X-rays from laser wakefield-accelerated electrons, have compact sizes, fs pulse duration and fs pump-probe capability, making it promising for wide use in material and biological sciences. Currently the main problem with such betatron X-ray sources is the limited average flux even with ultra-intense laser pulses. Here, we report ultra-bright betatron X-rays can be generated using a clustering gas jet target irradiated with a small size laser, where a ten-fold enhancement of the X-ray yield is achieved compared to the results obtained using a gas target. We suggest the increased X-ray photon is due to the existence of clusters in the gas, which results in increased total electron charge trapped for acceleration and larger wiggling amplitudes during the acceleration. This observation opens a route to produce high betatron average flux using small but high repetition rate laser facilities for applications.