Underwater pulsed spark discharge influenced by the relative position between the top of a pin electrode and an insulating tube

Needle-to-plane geometry has been widely investigated and used in underwater pulsed discharges.The position relationship between the needle tip and insulation layer significantly affects the discharge patterns.We carried out experiments on underwater pulsed discharge with the needle tip protruding from,recessing into,and flushing with the insulating tube.The results are as follows.First,underwater pulsed discharge has a strong randomness under the experimental conditions.Different discharge patterns appeared under the same experimental environment.Second,recession into the insulator surface led to a higher probability of occurrence but a lower strength of spark discharge than protrusion.Third,between the needle tip protruding from and recessing into the insulation material,the average speed of propagation of underwater pulsed spark discharge decreased by an order of magnitude.The study shows that the optimum length of needle tip protruding from the insulation layer is 1 mm to obtain a strong underwater pulsed spark discharge.

High-stability double-layer polymer-inorganic composite electrolyte fabricated through ultraviolet curing process for solid-state lithium metal batteries

Electrolyte interface resistance and low ionic conductivity are essential issues for commercializing solid-state lithium metal batteries(SSLMBs).This work details the fabrication of a double-layer solid composite electrolyte(DLSCE)for SSLMBs.The composite comprises poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and poly(methyl methacrylate)(PMMA)combined with 10 wt.%of Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO),synthesized through an ultraviolet curing process.The ionic conductivity of the DLSCE(2.6×10^(-4) S·cm^(-1))at room temperature is the high lithium-ion transference number(0.57),and the tensile strength is 17.8 MPa.When this DLSCE was assembled,the resulted LFP/DLSCE/Li battery exhibited excellent rate performance,with the discharge specific capacities of 162.4,146.9,93.6,and 64.0 mA·h·g^(-1) at 0.1,0.2,0.5,and 1 C,respectively.Furthermore,the DLScE demonstrates remarkable stability with lithium metal batteries,facilitating the stable operation of a Li/Li symmetric battery for over 200 h at both 0.1 and 0.2 mA-cm^(-2).Notably,the formation of lithium dendrites is also effectively inhibited during cycling.This work provides a novel design strategy and preparation method for solid composite electrolytes.