Synergistic Modulation of Nanoscale Architectures and Electronic Structures in Co–Ni Bimetallic Hydroxides for Enhanced Redox Kinetics in Supercapacitors

High Resolution Image Download MS PowerPoint Slide The strategic design of electroactive materials with optimized architecture is fundamental to achieving high-performance supercapacitors. While structural regulation via structure-directing agents (SDAs) has proven effective for zeolitic imidazolate framework-67 (ZIF67) derivatives, the intrinsic electronic limitations of monometallic systems often hinder further electrochemical improvements. This study explores the synergistic effects of cobalt-to-nickel ratios in metal hydroxides synthesized via a simple one-step solution process involving ammonium hydrogen fluoride and ammonia borane fluoride as SDAs. We demonstrate that the integration of Co and Ni ions significantly dictates the nucleation kinetics, leading to the formation of vertically aligned nanosheet arrays with optimized pore architectures. Electronic modulation at the metal centers is confirmed which facilitates charge transfer compared to single-metal counterparts. Specifically, the optimal bimetallic electrode exhibits a superior specific capacitance ( C F ) of 1207.6 F g –1 at 20 mV s –1, attributed to its reduced ion-diffusion resistance and balanced redox activity. An asymmetric energy-storage device employing the optimal bimetallic electrode delivers a maximum energy density of 20.08 Wh kg –1 at 600 W kg –1 and excellent long-term durability, with a C F retention of 85.2% over 10,000 cycles. These findings highlight the critical role of compositional engineering in unlocking the full potential of ZIF-derived bimetallic materials for future energy technologies.