All-gas-phase preparation of organic/inorganic heterolayered multifunctional electrodes for hybrid-type energy storage

Abstract

Lithium-ion hybrid capacitors (LHCs) are increasingly recognized as promising energy storage devices due to their ability to achieve high energy density while delivering rapid power delivery. In this study, a novel class of multifunctional electrodes for nonaqueous LHCs was developed by conjugating graphene (G), tungsten diselenide (W), and polypyrrole (PPy) into a heterolayered ternary nanohybrid (HTNH) structure. The integration of gas-phase processing techniques, including air-jet milling and vapor-phase polymerization, enabled the efficient, gram-scale production of HTNHs without the need for additional purification steps. Spectroscopic analyses confirmed the formation of HTNHs, highlighting significant interlayer interactions that synergistically enhance the properties of the individual components through their conjugation within the HTNH structure. The integration of PPy with GW to form graphene–WSe₂–PPy (GWP) nanohybrids resulted in a significant improvement in specific capacities, accompanied by a high working voltage of 4.5 V. In the half-cell configuration, the reversible specific capacities of GWPs were found to depend on the PPy content deposited. The optimized GWP sample exhibited the highest capacity of 182.9 mA h g⁻¹ (@0.1 A g⁻¹) and demonstrated exceptional cycling stability, retaining 91% of its capacity after 1000 cycles. These findings emphasize the importance of optimizing PPy incorporation to balance electrochemically active site availability and charge transport efficiency, thereby facilitating the rational design of advanced hybrid energy storage systems. In the full-cell configuration, the GWP HTNH demonstrated well-balanced performance, delivering a high energy density of 256 W h kg⁻¹ and a power density of 24 461 W kg⁻¹, surpassing previously reported materials with similar compositions.