摘要 |
<p>A separator for use in zinc/bromine secondary batteries comprising a polyethylene having an overall viscosity average molecular weight of not less than 350,000 and not more than 2,000,000 in which polyethylene a proportion of a polyethylene having a weight average molecular weight of not less than 1,000,000 is not less than 10 wt.% and not more than 80 wt.%, and fine particulate silica, wherein the ratio by weight of polyethylene/fine particulate silica is more than 1 and less than 1.5, and the ratio of the number of silicon atoms (Si) to the number of carbon atoms (C), Si/C, exposed on the surfaces of said separator excluding cross-sectioned surfaces thereof is not less than 0.01 and less than 0.2 as determined by X-ray photoelectron spectroscopy (XPS).</p> |