In -situ formed free-standing Ir nanocatalysts as carbon- and binder-free cathode for rechargeable nonaqueous Li -O 2 batteries

The design of carbon- and binder-free cathodes to replace the vulnerable carbon cathodes has become very imperative to further enhance the cycling performance of Li–O2 battery. Herein, free-standing Ir nanocatalyst as a novel carbon- and binder-free cathode is first proposed for rechargeable nonaqueous Li–O2 batteries. Impressively, the Li–O2 battery with freestanding iridium cathodes can maintain more than 67 stable cycles with a limited capacity of 800 mAh g−1 at a current density of 400 mA g−1. Greatly improved energy efficiency and rate capability are also successfully achieved. The iridium nanocatalyst is revealed to promote the discharge product formation via a newly desirable surface growth coupled with solution driven mechanism. This study sheds a new light on the role of iridium nanocatalyst, and provides a rational approach for the design of carbon- and binder-free cathodes of Li–O2 batteries. © 2020 Elsevier B.V.