posted on 2022-01-26, 12:03authored byJizhang Chen, Minfeng Chen, Weijun Zhou, Xinwu Xu, Bo Liu, Wenqing Zhang, Chingping Wong
MXenes have been intensively studied
for electrochemical energy
storage and other applications. However, time-consuming multistep
procedures involving hypertoxic HF or alike are utilized in conventional
synthesis methods of MXenes. Besides, −F terminal functional
groups inevitably exist in these MXenes, detrimental to supercapacitor
and battery performances. Herein, we develop a facile and time-saving
electrochemical etching method to synthesize F-free and Cl-containing
Ti3C2Tx in a mixed
LiOH and LiCl aqueous solution with an etching efficiency of 92.2%.
During the synthesis, sonification alone is able to delaminate Ti3C2Tx without using
any hazardous organic intercalant. The obtained delaminated Ti3C2Tx flakes are ∼3.8
μm in lateral size and ∼3.9 nm in thickness, and can
be stable in an aqueous dispersion for at least 15 days. The filtrated
Ti3C2Tx film is
20.5 MPa in tensile strength, 13.4 GPa in Young’s modulus,
and 1663 S cm–1 in electrical conductivity, and
exhibits specific capacitances of 323.7 F g–1, 1.39
F cm–2, and 1160 F cm–3 for supercapacitors.
Also, a flexible zinc-ion hybrid capacitor with energy density values
of 20.8 mWh cm–3 and 249.9 μWh cm–2 is assembled by using the Ti3C2Tx film as the cathode, and can maintain almost all
its capacity under bending.