An integrated architecture of mutually infiltrated nanoarray cathode and polymer electrolyte improves the performances of solid-state lithium−oxygen batteries

Abstract

In solid-state lithium−oxygen (Li−O2) batteries, solid polymer electrolytes (SPEs) usually cannot efficiently infiltrate into porous cathodes to form sufficient cathode/electrolyte/oxygen triple-phase interfaces for oxygen reduction reactions. The confined cathode/SPE interfaces in cathode/SPE/lithium anode sandwich-type cells only provide limited reaction sites accessible to lithium ion, electron, and oxygen gas. The resulted high interface resistances challenge the practical application of solid-state Li−O2 batteries. This work proposes an integrated architecture of mutually infiltrated nanoarray cathode and polymer electrolyte to produce more active sites and therefore lower the interface resistance. In detail, the integrated assemblies of cathode and SPE (Co3O4@CC-SPE) are prepared via partially infiltrating polymer and salt solution into Co3O4 nanosheets array (Co3O4@CC). The abundant cathode/SPE/oxygen triple-phase interfaces and the three-dimensional ion and electron-conducting networks in the Co3O4@CC-SPE assemblies achieve lower polarization, higher reversible capacity, and prolonged cycle life of solid-state Li−O2 batteries. The Co3O4@CC-SPE/Li cell shows a higher discharge capacity of 3.3 mA h cm−2 (6600 mA h g−1) and a higher 101 stable cycles than the 1.2 mA h cm−2 (2400 mA h g−1) and only 15 cycles of the sandwich-type counterparts. The present work provides new opportunities for developing practical solid-state Li−O2 batteries via the mutually infiltrated nanoarray cathode and polymer electrolyte.