Naphthalene Diimide‐Diketopyrrolopyrrole Polymer Composites (DPP‐NDI‐T2/MWCNT) as High‐Voltage Symmetric Supercapacitor Electrodes
Nitin V. Dalvi, Swati Dilwale, Sarika Sasidharan, Athira Babu, Radhakisan Kargude, Sreekumar Kurungot, Asha SyamakumariABSTRACT
We report the synthesis of donor–acceptor π‐conjugated polymer composites based on naphthalene diimide (NDI) and diketopyrrolopyrrole (DPP) (DPP‐NDI‐T2/MWCNT) for high‐voltage symmetric supercapacitor applications. DPP‐NDI‐T2 copolymers were synthesized by Stille polymerization and doped with varying loadings of multiwalled carbon nanotube (MWCNT). By varying the NDI:DPP feed ratio from 15 to 50 mol%, three copolymers ( P1 , P2 , and P3 ) were obtained. Polymer P3 was further fabricated into composites containing 20% ( C1 ), 35% ( C2 ), and 50% ( C3 ) MWCNT. These composites exhibited significantly improved conductivity, surface area, and porosity, with the 35% MWCNT composite ( C2 ) delivering a high specific capacitance of 304.2 F g − 1 at 1.0 A g − 1 in a three‐electrode assembly. The symmetric device C2||C2 in 1 M LiClO 4 shows the capacitance of 102.8 F g − 1 at 1.0 A g − 1 with the wide voltage window of 3.0 V (0 to 3 V) and the ultra‐high cycling stability over 100,000 charge–discharge cycles with capacitance retention of 98.4%, high power and energy density of 1500 W kg − 1 and 32.1 Wh kg − 1 , respectively. These results demonstrate the strong potential of conjugated composite polymer for next‐generation high‐performance energy storage devices.