A Novel NbPO5-CoFe2O4 Hybrid Electrode Toward Enhanced Electrochemical Energy Storage and Conversion

Abstract

In this study, a novel NbPO-CoFe composite electrode synthesized through a two-step process combining hydrothermal growth and electrodeposition is reported. The resulting 3D architecture offers excellent conductivity, structural stability, and abundant electroactive sites due to the synergy between NbPO₅ nanorods and CoFe₂O₄ nanoparticles, enabling efficient charge transport and enhance redox kinetics for bifunctional energy applications. Electrochemical evaluation reveals NbPO-CoFe has a high areal capacitance of 15.09 F cm^{- 2} (2.52 mAh cm^{- 2}) at 20 mA cm^{- 2}. An asymmetric supercapacitor device (NbPO-CoFe//AC) is fabricated that demonstrates excellent cycling stability retaining 85% of its capacitance and 95% coulombic efficiency till 45 000 cycles. Complementing experimental observations, machine learning analysis using the Prophet model forecasts enhanced long-term stability, suggesting the composite's robust potential in practical applications. Beyond energy storage, the NbPO-CoFe composite demonstrates outstanding oxygen evolution reaction performance, with a low overpotential of 210 mV at 10 mA cm⁻², confirming its suitability for water-splitting applications. The device's practical viability is further showcased by its ability to power red (≈1.5 V), green (≈2.0 V), and blue (≈3.0 V) LEDs. These findings position the NbPO-CoFe composite as a high-performance, multifunctional electrode material with strong prospects in advanced electrochemical energy storage and sustainable catalysis technologies.

Keywords: NbPO@CoFe; bi‐functional; energy storage and conversion; exceptional‐cyclability; machine learning stability.