LAUSR

Although asymmetric supercapacitors (ASCs) can achieve high energy density, the lifespan and power density are severely suppressed due to the low conductivity of using pseudocapacitive or battery-type electrode materials. Recently, nonporous conductive coordination polymers (c-CPs) have sparked interests in supercapacitors. However, their performance is expected to be limited by the nonporous features, low specific surface area and absence of ion-diffusion channels. Here, it is demonstrated that the capacity of nonporous CPs will be significantly enhanced by maximizing the number of faradaic redox sites in their structures through a comparative investigation on three highly conductive nonporous c-CPs, Cux BHT(x = 3, 4, 5.5). They show excellent capacitance of 312.1 F g-1 (374.5 C g-1 ) (Cu3 BHT), 186.7 F g-1 (224.0 C g-1 ) (Cu4 BHT) and 89.2 F g-1 (107.0 C g-1 ) (Cu5.5 BHT) at 0.5 A g-1 in a sequence related to the number of electron storage units in structures and outstanding rate performance and cycle stability. Furthermore, the constructed Cu3 BHT//MnO2 ASC device exhibits capacity retention of 92% (after 1500 cycles at 3 A g-1 ) and delivers a high energy density of 39.1 Wh kg-1 at power density of 549.6 W kg-1 within a large working potential window of 0-2.2 V.