Cathode Chemistries of Lithium–Oxygen Batteries in Nanoconfined Space
Hongyu Liu, Zhaohan Shen, Zheng‐Ze Pan, Wei Yu, Hirotomo Nishihara
Abstract
In lithium–oxygen batteries, although the porous carbon cathodes are widely utilized to tailor the properties of discharged Li 2 O 2, the impact of nanopore size on the Li 2 O 2 formation and decomposition reactions remain incompletely understood. Here, we provide the straightforward elucidation on the effect of pore size in a range of 25–200 nm, using a highly ordered porous cathode matrix based on the carbon-coated anodic aluminum oxide membrane formed on an Al substrate (C/AAO_Al). When the nanopore size is 25 nm, film-like Li 2 O 2 with a thickness of 2–5 nm is formed, possibly via a surface-driven mechanism. When the nanochannel becomes larger, the Li 2 O 2 film thickness saturates at ca. 10 nm, along with crystalline Li 2 O 2 particles possibly formed by a solution-mediated mechanism.