A current collector covering nanostructured villous oxygen-deficient NiO fabricated by rapid laser-scan for Li-O2 batteries

Abstract

Non-aqueous Li-O2 batteries attract extensive attention because of their ultra-high theoretical specific energy density. However, the high charge potential, which induces severe parasitic reactions such as the corrosion of carbon-based catalysts and metal current collectors, is one of the biggest challenges currently. Herein, a current collector of Ni foam covering nanostructured villous NiO with oxygen vacancies (NiO1-δ) was fabricated by a fast laser-scan technique. The modified NiO1-δ based current collector presented superior stability and comparable electrocatalytic activity. It delivered a discharge capacity of about 500 mAh g−1 and a low charge potential of 3.84 V in a Li-O2 cell in the absence of catalysts. And this cell could maintain 73.5% of the initial capacity after 100 full discharge-charge cycles. Density functional theory (DFT) calculations verified that the improved electrocatalytic activity mainly derived from the introduction of oxygen vacancies in NiO1-δ. It improved the electronic conductivity for rapid electron transfer as well as served as active sites to bind O2 and oxygen-containing intermediates (eg. LiO2) for electrochemistry reactions. This work gives a rapid and easily mass-produced method to fabricate a stable and activated current collector for Li-O2 batteries.