Wettability-Controlled Tri-continuous Carbon-based Electrocatalysts for Zn-Air Batteries

¹ Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, United States
² Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, United States
³ Department of Chemical Engineering, Inha University, Incheon 22212, Republic of Korea

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it. and This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Zn-air batteries (ZABs) are promising energy storage systems, but their performance is often limited by sluggish oxygen reduction reaction (ORR) kinetics and electrolyte flooding at the air cathode. Here, we introduce a tri-continuous carbon-based electrocatalyst (TRICE) derived from bijels-templated carbonization to address these challenges. The resulting nanoporous framework provides interconnected channels for air and electrolyte, enhancing three-phase boundary formation and mass transport. To investigate the role of wettability, two TRICE samples, specifically unmodified and hydrophobic TRICE were evaluated. The hydrophobic TRICE electrodes exhibited strong resistance to electrolyte flooding and maintained stable electrochemical operation during repeated cycling. Despite being fully metal-free, their power densities remained competitive with those of noble-metal and metal-oxide air cathodes. These results demonstrate that wettability tuning in TRICE structures effectively improves flooding tolerance and air cathode stability, offering a promising pathway for durable ZABs.