Cold pressing-built microreactors to thermally manipulate microstructure of MXene film as an anode for high-performance lithium-ion batteries

Abstract

In order to fully excavate Ti3C2Tx's electrochemical energy storage capability, a combination of cold pressing and annealing treatment is developed to fabricate free-standing Ti3C2Tx MXene films featuring well-defined film structure, planar macropores, in-plane defects and expanded interlayer spacing. The rational construction of microreactors between Ti3C2Tx nanosheets by cold pressing can assist the formation of the planar macropores and in-plane defects of Ti3C2Tx nanosheets under the annealing conditions, whereas the annealing process could regulate the functional groups of Ti3C2Tx nanosheets to significantly expand their interlayer spacing. These structural advantages not only can prevent self-restacking of Ti3C2Tx nanosheets, but also can increase the ion and electrolyte diffusion as well as the utilization of electrochemically active sites. The as-prepared PF-Ti3C2Tx-500, pre-pressed at 6 MPa followed by an annealing treatment at 500 °C in H2/Ar, exhibits excellent characteristics as the lithium storage anode, such as an enhanced initial Coulombic efficiency (CE) of 77.3%, a high areal capacity (2.22 mA h cm−2 at 7.52 mg cm−2 for 500 cycles), and stable long cycling performance. This work demonstrates the important role of microstructure manipulation of Ti3C2Tx MXene on their electrochemical performance and can guide future work on designing high-performance MXene-based materials for energy storage applications.