Abstract
We present a universal protocol for the construction of alternating stacked micrometer-thick graphene-conducting  polymer compact hybrid fi lms with landmark areal and volumetric capacitances for high-energy MSCs, by taking advantages of the strong coupling and synergistic effect of 2D pseudocapacitive graphene-conducting polymer nanosheets and electrochemically exfoliated graphene (EG). The 2D graphene-based compact films of “PxGy ” where x and y represent the number of deposited graphene-conducting polymer layers ( x ) and EG layers ( y = x + 1) are prepared by alternating deposition of the layers of EG and sandwich-like mesoporous graphene-conducting polymer nanosheets, e.g., polyaniline-functionalized graphene (PANI-G) nanosheets or polypyrrole-functionalized graphene (PPY-G) nanosheets. The resultant layer-stacked nanohybrid films are highly conductive (2120 S m −1 ), uniform, and nanoporous, yet densely packed (1.67 g cm −3 ). Notably, they can simultaneously deliver an ultrahigh areal capacitance of 368 mF cm −2 and a andmark volumetric capacitance of 736 F cm −3 at 10 mV s −1 for MSCs fabricated based on P2G3 film on the polyethylene terephthalate (PET) substrate, using 16 nm PANI-G nanosheet in aqueous H2SO4 electrolyte (denoted as P2G3-MSCs-D), both of which are the highest values among the reported state-of-theart MSCs. The all-solid-state MSCs fabricated based on P2G3 film on PET substrate using H2SO4 /polyvinyl alcohol (PVA) gel electrolyte (denoted as P2G3-MSCs-C) with 210 mF cm −2 and 436 F cm −3 at 10 mV s −1 exhibit remarkable mechanical flexibility without any performance deterioration under bending. Furthermore, the tandem integrated MSCs can effi ciently power high-voltage light-emitting diodes. Remarkably, the volumetric energy density of 46 mWh cm −3 (10 mV s −1 ) achieved with compact MSCs based on P2G3 film in ionic liquid electrolyte (1-ethyl-3-methylimidazolium tetrafluoroborate, EMIMBF4 ), denoted as P2G3-MSCs-E, is much higher than those of the state-of-the-art MSCs, and LTF batteries (≤10mWhcm−3 )