Fast development of smart electronics requires urgently intergrated energy storage devices, but conventional supercapacitors, using two substrates, suffer from weak flexibility, low energy density and inferior integration. Here we demonstrate a printable construction of all-solid-state high-energy planar asymmetric supercapacitors (EG//MP-PASCs) based on all-in-one monolithic films of stacked-layer pseudocapacitive MnO2/poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate) (MP) nanosheets as positive electrode, highly ionic conductive boron nitride nanosheets as ultrathin separator (~2.2 μm), and capacitive electrochemically exfoliated graphene (EG) nanosheets as negative electrode integrated on single substrate. Notably, EG//MP-PASCs are free of conventional separators, additives, binders, and metal-based current collectors, significantly simplifying the device fabrication process. EG//MP-PASCs can be operated reversibly at high voltage of 1.8 V at polyvinyl alcohol/LiCl gel electrolyte, and exhibit volumetric energy density of 8.6 mWh cm−3, much higher than those of conventional asymmetric supercapacitors based on two substrates (3.1 mWh cm−3), planar symmetric supercapacitors based on EG//EG (0.64 mWh cm−3), MP//MP (2.5 mWh cm−3). Further, EG//MP-PASCs display robust mechanical flexibility with ~98.8% of initial capacitance even bended at 180°, and applicable scalability on various substrates. Remarkably, EG//MP-PASCs can be readily self-interconnected in series and parallel, without usage of metal-based interconnections and contacts, to tailor the voltage and current output for integrated circuits.