Longevous Protic Hybrid Supercapacitors Using Bimetallic Prussian Blue Analogue/rGO-Based Nanocomposite Against MXene Anode

MXenes exhibit a unique combination of properties—2D structure, high conductivity, exceptional capacity, and chemical resistance—making them promising candidates for hybrid supercapacitors (HSCs). However, the development of MXene-based HSCs is often hindered by the limited availability of cathode materials that deliver comparable electrochemical performance, especially in protic electrolytes. In this study, this challenge is addressed by introducing a durable protic HSC utilizing a bimetallic Prussian Blue Analogue (PBA) decorated on reduced graphene oxide (rGO) as a nanocomposite cathode paired with a single-layered Ti₃C₂T_x MXene (SL-MXene) anode. The bimetallic PBA, specifically nickel hexacyanocobaltate (NiHCC), is utilized by virtue of its open and stable structure that facilitates efficient charge storage, leading to enhanced stability and energy storage capabilities. The resulting NiHCC/rGO//SL-MXene cell demonstrates impressive performance, achieving a maximum specific energy of 38.03 Wh kg⁻¹ and a power density of 20 666.67 W kg⁻¹. Remarkably, the NiHCC/rGO//SL-MXene HSC cell also exhibits excellent cycling stability without any loss even after 15 000 cycles while retaining ≈100% coulombic efficiency. This work underscores the potential of bimetallic PBA materials with conductive rGO backbone for overcoming the limitations of current MXene-based protic HSCs, highlighting the significance of this work.