In Situ Coupling of Highly Dispersed Ni/Fe Metal-NC Sites and N-Doped 3D Carbon Fibers Toward Free-Standing Bifunctional Cathode for Flexible Zinc-Air Battery

Designing flexible free-standing air-electrode with efficient OER/ORR performance is of vital importance for the application of Zinc-air batteries in flexible electronics.Herein,a flexible free-standing electrode(Ni/Fe-NC/NCF/CC)is synthesized by in-situ coupling of binary Ni/Fe-NC nanocubes and N-doped carbon nanofibers(NCF)rooted on carbon cloth.The highly dispersed binary Ni/Fe-NC sites ensure excellent ORR activity and create efficient OER active sites relative to Ni-NC and Fe-NC.The in-situ coupling of Ni/Fe-NC and NCF constructs a 3D interconnected network structure that not only provides abundant and stabilized reactive sites but also guarantees fast electron transfer and gas transportation,thus achieving efficient and fast operation of ORR/OER.Therefore,Ni/Fe-NC/NCF/CC displays a much positive potential(0.952 V)at 4.0 mA cm^(-2)for ORR and a low OER overpotential(310 mV)at 50 mA cm^(-2).The Zinc-air battery with Ni/Fe-NC/NCF/CC air-electrode exhibits excellent battery performance with outstanding discharge/charge durability for 2150 cycles.The flexible Zn-air batteries with foldable mechanical properties display a high power density of 105.0 mW cm^(-2).This work widened the way to prepare flexible bifunctional air-electrode by designing composition/structure and in-situ coupling.

锡基钙钛矿太阳能电池研究进展

自2009年以来,有机-无机卤化物钙钛矿因其独特的光学和电学性能,在光电材料领域受到了广泛的研究,尤其是Pb基的卤化物钙钛矿太阳能电池,目前光电转换效率高达创纪录的约25.2%,显示出强大的商业化潜力。然而,Pb元素的毒性及因而导致的环境隐患问题,一直是其产业化过程中的顾虑之一。因此,寻求能替代Pb的环境友好的元素,是一个十分重要的课题。Pb基钙钛矿材料优异的光电特性来源于Pb^(2+)的最外层6s2孤对电子,与Pb元素同主族的Sn元素能够形成三维钙钛矿结构且同样具有惰性5s2外层电子结构,因而是替代Pb的首选。本文系统地介绍了Sn基钙钛矿的光学和电学性质,并从薄膜制备方法和不同的器件结构方面介绍Sn基钙钛矿太阳能电池的最新进展。