Engineering Triple-Phase Interfaces Enabled by Layered Double Perovskite Oxide for Boosting Polysulfide Redox Conversion.

Bai, Zhe; Wang, Zhenhua; Li, Ruilong; Wu, Zeyu; Feng, Pingli; Zhao, Lina; Wang, Tan; Hou, Wenshuo et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

The electrocatalytic conversion of polysulfides is crucial to lithium-sulfur batteries and mainly occurs at triple-phase interfaces (TPIs). However, the poor electrical conductivity of conventional transition metal oxides results in limited TPIs and inferior electrocatalytic performance. Herein, a TPI engineering approach comprising superior electrically conductive layered double perovskite PrBaCo<sub>2</sub>O<sub>5+δ</sub> (PBCO) is proposed as an electrocatalyst to boost the conversion of polysulfides. PBCO has superior electrical conductivity and enriched oxygen vacancies, effectively expanding the TPI to its entire surface. DFT calculation and <i>in situ</i> Raman spectroscopy manifest the electrocatalytic effect of PBCO, proving the critical role of enhanced electrical conductivity of this electrocatalyst. PBCO-based Li-S batteries exhibit an impressive reversible capacity of 612 mAh g<sup>-1</sup> after 500 cycles at 1.0 C with a capacity fading rate of 0.067% per cycle. This work reveals the mechanism of the enriched TPI approach and provides novel insight into designing new catalysts for high-performance Li-S batteries.