Electrochemical Properties Of Two Dimensional GO/Ti₃C₂T_x Nanocomposites As Li-ion Batteries Anode

MXene is a large class of carbide and/or nitride exfoliated from ternary layered transition metal carbide ceramic-MAX phase. Because of its unique electrical, magnetic properties and graphene-like layered structure, MXene has broad application prospects and study space in catalysis, energy storage and composite fields. This work chose the 312 phase of MAX phase- Ti3 Al C2 as precursor to be etched by HF for different time. After obtaining the best etching time, we exfoliated the etching product and achieved few-layered Ti3C2 Tx sheets(T stands for –O,-OH,-F functional group). The graphene oxide(GO)/Ti3C2 Tx composites were synthesi zed to study the influence of graphene oxide addition and reduction processing to the component, microstructure, valence distribution and electrochemical properties.40wt.% HF was used to etch Ti3 Al C2 for different time(2h,4h,8h,24h). The results demonstrated that after etching for 24 h, the Al atom layer was etched with larger layer spacing and all the powders were etched completely. The 24 h powders were exfoliated successfully and we got the few-layered Ti3C2 Tx sheets. The Ti3C2 T x sheets were thin electron transparent flakes with curled edges.The GO/Ti3C2 Tx composites were synthesized by the method of mixing sonication afer exfoliation with 10 wt.%~40wt.% of graphene oxide addition. After adding graphene oxide, the content of Ti3C2(OH)2 decreased with Ti3 Al C2-li ke structure and the electrochemical properties improved. The electroche mical properties of 20%GO/Ti3C2 Tx was the best with a specific capacity of 577.6mAh/ g in the fist charge, the specific capacity can also possess 118.2 mAh/g after 100 cycles, revealing good cyclic performance.Due to the functional groups in GO/Ti3C2 Tx composites influence the electrochemical properties dramatically, reduction processing was needed to eliminate the groups.The reduction processing was carried out in Ar atmosphere at 1200 oC for 2h. After reduction, the content of-OH and –F groups decreased considerably with serious agglomeration. The specific capacity of GO/Ti3 C 2T x composites increased with the addition of graphene oxide after reduction processing. The electrochemical properties of 40%GO/Ti3C2 Tx was the best with a specific capacity of 311.5mAh/g in the fist discharge and good cyclic performance The reason for the sharply decline of specific capacity of GO/Ti3C2 Tx by 2 times after reduction could be the agglomeration of reduction product which impeded the diffusion of Li ion between the layers in GO/Ti3C2 Tx composites.