ALD-enabled WO₃-MoO₃ nanohybrid heterostructure for high-performance electrochemical supercapacitors

To achieve high -performance electrochemical supercapacitors (ESCs), it is crucial to control thin-film electrode fabrication. The uniform thickness of these electrodes is of paramount importance as it enables the rapid electrochemical responses during the charge-discharge processes, facilitated by their shorter charge and ion diffusion lengths. This research presents a WO3-MoO3 wafer-scaled nanohybrid electrode with a thickness of less than 10.0 nm for ESCs applications fabricated by atomic layer deposition (ALD) technique. The developed heterostructure electrode exhibited high purity, well-defined crystallinity and uniform morphology, enabling efficient pseudocapacitive Faradaic redox reactions with good reversibility. Notably, the fabricated electrode displayed impressive super-capacitive performance, delivering a specific capacitance (C-s) of up to 1094.80 and 803.10 F g(-1) at scan rates of 5 mV/s and a high current density of 19.23 A g(-1), respectively. The enhanced energy storage capacity of this heterostructure can be attributed to the improved redox activity and reduced ion diffusion length facilitated by the WO3-MoO3 nanohybrid thin-films. Additionally, the electrode demonstrated outstanding electrochemical stability with Cs retention of similar to 93.25 % after 5000 galvanostatic charge/discharge cycles.