A MXene-based EDA-Ti3C2Tx intercalation compound with expanded interlayer spacing as high performance supercapacitor electrode material

Expanding the interlayer spacing of the Ti3C2Tx MXene structure is realized by intercalation of ethylenediamine (EDA), which is anchored on the surface of Ti3C2Tx sheets by one side amino groups with N–Ti coordination bonds. The EDA-Ti3C2Tx intercalation compound has a high specific surface area of 59.2 m2 g−1 with mainly mesopores. The EDA-Ti3C2Tx possesses the low charge transfer resistances of ∼0.32/0.28 Ω in 1/3 M H2SO4 aqueous electrolytes, respectively. A large specific capacitance of 486.2 F g−1 (1312.7 F cm−3) is obtained for EDA-Ti3C2Tx at a scan rate of 2 mV s−1 in 1 M H2SO4 electrolyte, showing its high capacitance property. A good specific capacitance of 249.4 F g−1 (673.4 F cm−3) is retained at larger scan rate of 100 mV s−1, indicating its significantly high rate capability. Higher specific capacitances of 563.3 (1520.9), 522.1 (1409.7), 485.1 (1309.8), 436.2 (1177.7), 356.2 (961.7) and 290.6 F g−1 (784.6 F cm−3) are achieved for EDA-Ti3C2Tx at the scan rates of 2, 5, 10, 20, 50 and 100 mV s−1, respectively, in 3 M H2SO4 electrolyte. The cyclic retention of EDA-Ti3C2Tx after 10,000 cycles reaches 89.7% at 10 A g−1 in 3 M H2SO4 electrolyte, showing the excellent cyclic stability.