Three-Dimensional Ti₃C₂T_x MXene-Prussian Blue Hybrid Microsupercapacitors by Water Lift-Off Lithography

The construction of electrochemical energy-storage devices by scalable thin-film microfabrication methods with high energy and power density is urgently needed for many emerging applications. Herein, we demonstrate an in-plane hybrid microsupercapacitor with a high areal energy density by employing a battery-type CuFe-Prussian blue analogue (CuFe-PBA) as the positive electrode and pseudocapacitive titanium carbide MXene (Ti₃C₂T_x) as the negative electrode. A three-dimensional lignin-derived laser-induced graphene electrode was prepared as the substrate by laser exposure combined with an environmentally friendly water lift-off lithography. The designed hybrid device achieved enhanced electrochemical performance thanks to the ideal match of the two types of high-rate performance materials in proton-based electrolytes and the numerous electrochemically active sites. In particular, the device delivers a high areal capacitance of 198 mF cm^-2, a wide potential window (1.6 V), an ultrahigh rate performance (75.8 mF cm^-2 retained even at a practical/high current density of 100 mA cm^-2), and a competitive energy density of 70.5 and 27.6 μWh cm^-2 at the power densities 0.74 and 52 mW cm^-2, respectively. These results show that the Ti₃C₂T_x/CuFe-PBA hybrid microsupercapacitors are promising energy storage devices in miniaturized portable and wireless applications.