Laser-assisted fabrication of a 3D cross-linked V2CTx/rGO microelectrode for high-rate aqueous zinc-ion microbatteries

Abstract

The high safety, compatible device size, superior energy density, and cost efficiency make in-plane aqueous zinc-ion microbatteries (AZIMBs) one of the most promising candidates for miniaturized energy storage. However, the inherent stacking structure within in-plane AZIMBs poses a hindrance to improving their energy density. Herein, this work presents a one-step approach for fabricating 3D cross-linked structures in V₂CT_x@rGO microelectrodes by laser processing technology, aiming to enhance the electrochemical performance of AZIMBs within a limited area by exploiting the vertical dimension of 3D architectures. The laser heat generated during laser processing induces the conversion of a 2D V₂CT_x@GO stacked structure into a 3D V₂CT_x@rGO skeleton structure, enabling the microelectrode to possess an optimal 3D conductive network, efficient charge transport pathway, and complete exposure of active sites. Moreover, the utilization of vanadium-based oxides derived from V₂CT_x MXene nanosheets on the surface during charging enhances the electrochemical performance of 3D AZIMBs. The obtained 3D VO_x-V₂CT_x@rGO microelectrodes exhibit excellent rate performance, demonstrating an average reversible capacity ranging from 459 to 342 mA h g⁻¹ at current densities varying from 0.8 to 2.5 A g⁻¹, respectively. Additionally, the fabricated 3D VO_x-V₂CT_x@rGO AZIMBs demonstrate exceptional flexibility and integrability, thus showing significant potential in microsized energy storage devices.