A Carbon-Free and Free-Standing Cathode From Mixed-Phase TiO2 for Photo-Assisted Li-CO2 Battery

Lizhen Long; Yaya Ding; Nina Liang; Jun Liu; Fuchi Liu; Sheng Huang; Yuezhong Meng

doi:10.1002/smll.202300519

A Carbon-Free and Free-Standing Cathode From Mixed-Phase TiO₂ for Photo-Assisted Li-CO₂ Battery

Small. 2023 Jul;19(27):e2300519. doi: 10.1002/smll.202300519. Epub 2023 Mar 28.

Authors

Lizhen Long¹, Yaya Ding¹, Nina Liang¹, Jun Liu¹, Fuchi Liu¹, Sheng Huang², Yuezhong Meng²

Affiliations

¹ School of Physical Science and Technology, Guangxi Normal University, Guilin, 541004, P. R. China.
² The Key Laboratory of Low-carbon Chemistry & Energy Conservation of Guangdong Province/State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, P. R. China.

PMID: 36974576
DOI: 10.1002/smll.202300519

Abstract

Li-CO₂ battery provides a new strategy to simultaneously solve the problems of energy storage and greenhouse effect. However, the severe polarization of CO₂ reduction and CO₂ evolution reaction impede the practical application. Herein, anodic TiO₂ nanotube arrays are first introduced as carbon-free and free-standing cathode for photo-assisted Li-CO₂ battery, and the photo-assisted charge and discharge mechanism is first clarified from the perspective of photocatalysis. Mixed-phase TiO₂ exhibits a long cycling life of 580 h (52 cycles) at 0.025 mA cm^-2 and delivers a high discharge specific capacity of 3001 µAh cm^-2 under UV illumination. The charge voltage dramatically reduces from 4.53 to 3.03 V under UV illumination. The improvement of photo-assisted Li-CO₂ battery performance relies on the synergistic effect of the hierarchical porous structure, strong UV absorption, efficient separation, and transfer of photo-generated electrons and holes at hetero-phase junction, and the facilitation of photo-generated electrons and holes on CO₂ reduction and CO₂ evolution reaction. This work can provide useful guidance for designing efficient photocathode for photo-assisted Li-CO₂ battery and other metal-air batteries.

Keywords: Li-CO 2 batteries; TiO 2; mixed phase; photo-assisted; photocatalysis.

Abstract

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