Advanced trifunctional electrodes for 1.5 V-based self-powered aqueous electrochemical energy devices

Energy devices with multifunctional applications, such as integrating two different energy devices, are emerging as promising strategies to elevate energy technology. This is, however, an alarming challenge that appeals to a single electrode material with multifunctional applications to minimize cost. Herein, a novel and cost-effective dual-functional self-powered aqueous electrochemical energy device (DAEED) was successfully assembled by integrating asymmetric supercapacitor (ASC) and overall water splitting (OWS) devices using a unique P-doped NiMoO 4 /MoO 2 (denoted NMO-MO-P) nanorods as the trifunctional electrode. NMO-MO-P exhibits excellent supercapacitor (SC) storage and oxygen evolution reaction (OER) catalytic ability owing to the tuning of the electronic structure synergistic interfacial and doping engineering. The as-prepared NMO-MO-P trifunctional electrode offers a 1.50 V operating NMO-based ASC device and a 1.50 V bifunctional NMO-based overall water splitting (OWS) in aqueous alkaline KOH solution. The similar operating potentials of both ASC and OWS devices allow the electrical energy stored by the NMO-based ASC device to simultaneously and in a self-powered way generate H 2 and O 2 from the as-assembled DAEED. This present work creates more opportunities towards achieving cost-effective EEDs technology. A novel 1.5 V aqueous self-powered electrochemical energy device involving the integration of asymmetric supercapacitors and overall water splitting is designed, where the phosphorus-doped NiMoO 4 /MoO 2 electrode plays a trifunctional role in the device.