Liquid Zn-Anode-Assisted molten salt electrolysis of CO2 to synthesize Zn@C/PC for Lithium-Ion battery anode

Abstract

Zinc-carbon composite materials are promising anode materials for lithium-ion batteries (LIBs). However, volume expansion of Zn deteriorates the capacity and cycling stability. Fabricating carbon-encapsulated Zn structures represents an effective strategy for mitigating the volume expansion of Zn. In this study, we present a facile molten salt electrolysis approach, in which a liquid Zn anode and CO2 were strategically utilized to facilitate the synthesis of core–shell Zn@C nanospheres embedded in a honeycomb-like porous carbon matrix (Zn@C/PC). The Zn2+ ions, generated in-situ through the oxidation of Zn anode surface, undergo co-reduction with the CO2-replenished CO32–, resulting in the production of Zn@C/PC series. Benefiting from its composition and structure, the optimal Zn@C/PC shows high reversible capacity (1271 mA h g−1 at 50 mA g−1) and superior cycling stability, with a capacity retention rate of 81.4 % after 1250 cycles under 2 A g−1. The introduced liquid-anode-assisted molten salt electrolysis offers a novel approach for producing high-performance energy storage materials. Moreover, conversion of CO2 into materials applicable to energy applications represents a promising pathway for advancing carbon neutrality.