Synergistic optimization of NCM9055/AC composites enabling superior performance in hybrid battery-supercapacitors

Owing to sluggish ion migration, structural instability, and elevated interfacial impedance, ternary lithium nickel cobalt manganese oxide (NCM) systems often fail to meet the requirements of rapid charge-discharge, resulting in low power densities in lithium-ion batteries (LIBs). This study investigates the electrochemical performance of cathodes fabricated via the integration of three types of ternary NCM material (namely NCM523, NCM811, and NCM9055) composited with activated carbon (AC) for hybrid battery supercapacitors (HBS). Attributed to the highly uniform morphology, enhanced structural stability, and high Ni percentage, NCM9055/AC composite cathodes not only a superior specific capacity (231 mAh/g at 0.1 C) but also exceptional rate charge and discharge performance and long cycling stability. At a current density of 0.5 C, the NCM9055/AC composite cathode maintained a high capacity of 222 mAh/g. Even at a high current density of 5 C, NCM9055/AC composite cathodes delivered a reversible capacity of 153 mAh/g with a retention of 79.4% after 360 cycles. Outperforming the NCM811/AC and NCM523/AC composite cathodes, demonstrating that synergistic optimization can indeed achieve the objectives of high capacity, enhanced rate capability, and improved cycling stability. Furthermore, the assembled pouch HBS, constructed with one NCM9055/AC composite cathode and two graphite anodes, achieved an energy density of 55 Wh/kg, a power density of 1,828 W/kg, and a capacity retention up to 99% after 340 cycles at 0.5 C. This indicates exceptional potential for fast charging and long cycle life, providing an innovative technical solution for application scenarios requiring high energy and rapid response.