Recycling Ti3C2T x Oxide Nanosheets through Channel Engineering: Implications for High-Capacity Supercapacitors

Channel (hole and interlayer) engineering on two-dimensional(2D)MXenes has been proven to be an effective strategy to solve the issuesof congested ion transport pathways, limited active sites, and sluggishion transport kinetics caused by restacking of MXene nanosheets, whichextended the application in the field of energy storage. Herein, asimple channel engineering strategy was proposed to treat the long-termstored Ti3C2T x nanosheets,resulting in formation of an interlayer-expanded holey Ti3C2T x film via etching outTi(3)C(2)T( x ) oxides.The in situ oxides expanded the interlayer spacing and created holeson the Ti3C2T x nanosheets,which formed channels in all directions. The interlayer-expanded holeyTi(3)C(2)T( x ) film showedoutstanding electrochemical performance, with both high capacity (448F g(-1) at 2 mV s(-1)) and good cyclicstability (95.3% retention after 5000 cycles). Importantly, this strategyeffectively recycles the waste MXenes that are oxidized by long-termstorage, which embodies the concept of low carbon and environmentalprotection and promotes the industrialization process of MXenes.