Development of electrode materials with well-defined architectures is a fruitful and profitable approach for achieving highly-efficient energy storage systems. A molecular-scale hybrid system is presented based on the self-assembly of CoNi-layered double hydroxide (CoNi-LDH) monolayers and the conducting polymer (poly(3,4-ethylene dioxythiophene): poly(styrene sulfonate), denoted as PEDOT: PSS) into an alternating-layer superlattice. Owing to the homogeneous interface and intimate interaction, the resulting CoNi-LDH/PEDOT: PSS hybrid materials possess a simultaneous enhancement in ion and charge-carrier transport and exhibit improved capacitive properties with a high specific capacitance (960 F g(-1) at 2 A g(-1)) and excellent rate capability (83.7% retention at 30 A g-1). In addition, an in-plane supercapacitor device with an interdigital design is fabricated based on a CoNi-LDH/PEDOT: PSS thin film, delivering a significantly enhanced energy and power output (an energy density of 46.1 Wh kg(-1) at 11.9 kW kg(-1)). Its application in miniaturized devices is further demonstrated by successfully driving a photodetector. These characteristics demonstrate that the molecular-scale assembly of LDH monolayers and the conducting polymer is promising for energy storage and conversion applications in miniaturized electronics.