Report

Proton transport enabled by a field-induced metallic state in a semiconductor heterostructure

See allHide authors and affiliations

Science  10 Jul 2020:
Vol. 369, Issue 6500, pp. 184-188
DOI: 10.1126/science.aaz9139

You are currently viewing the abstract.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution

This article has an editorial expression of concern. Please see:

A metallic route for protons

The operating temperatures of solid oxide fuel cells are usually much higher than needed to drive the uncatalyzed electrochemical reaction to transport oxygen anions or protons through ceramic electrolytes. Wu et al. report that the interface between two semiconductors, NaxCoO2 and CeO2, forms a metallic state that enables proton transport at temperatures below 600°C (see the Perspective by Ni and Shao). The authors constructed a hydrogen fuel cell with this material that delivered 1 watt per centimeter.

Science, this issue p. 184; see also p. 138

Abstract

Tuning a semiconductor to function as a fast proton conductor is an emerging strategy in the rapidly developing field of proton ceramic fuel cells (PCFCs). The key challenge for PCFC researchers is to formulate the proton-conducting electrolyte with conductivity above 0.1 siemens per centimeter at low temperatures (300 to 600°C). Here we present a methodology to design an enhanced proton conductor by means of a NaxCoO2/CeO2 semiconductor heterostructure, in which a field-induced metallic state at the interface accelerates proton transport. We developed a PCFC with an ionic conductivity of 0.30 siemens per centimeter and a power output of 1 watt per square centimeter at 520°C. Through our semiconductor heterostructure approach, our results provide insight into the proton transport mechanism, which may also improve ionic transport in other energy applications.

View Full Text

Stay Connected to Science