Phosphorus Regulated Cobalt Oxide@Nitrogen‐Doped Carbon Nanowires for Flexible Quasi‐Solid‐State Supercapacitors
Shude Liu, Ying Yin, Yang Shen, Kwan San Hui, Young Tea Chun, Jong Min Kim, Kwun Nam Hui, Lipeng Zhang, Seong Chan Jun
Abstract
Abstract Battery‐type materials are promising candidates for achieving high specific capacity for supercapacitors. However, their slow reaction kinetics hinders the improvement in electrochemical performance. Herein, a hybrid structure of P‐doped Co 3 O 4 (P‐Co 3 O 4 ) ultrafine nanoparticles in situ encapsulated into P, N co‐doped carbon (P, N‐C) nanowires by a pyrolysis–oxidation–phosphorization of 1D metal–organic frameworks derived from Co‐layered double hydroxide as self‐template and reactant is reported. This hybrid structure prevents active material agglomeration and maintains a 1D oriented arrangement, which exhibits a large accessible surface area and hierarchically porous feature, enabling sufficient permeation and transfer of electrolyte ions. Theoretical calculations demonstrate that the P dopants in P‐Co 3 O 4 @P, N‐C could reduce the adsorption energy of OH − and regulate the electrical properties. Accordingly, the P‐Co 3 O 4 @P, N‐C delivers a high specific capacity of 669 mC cm −2 at 1 mA cm −2 and an ultralong cycle life with only 4.8% loss over 5000 cycles at 30 mA cm −2 . During the fabrication of P‐Co 3 O 4 @P, N‐C, Co@P, N‐C is simultaneously developed, which can be integrated with P‐Co 3 O 4 @P, N‐C for the assembly of asymmetric supercapacitors. These devices achieve a high energy density of 47.6 W h kg −1 at 750 W kg −1 and impressive flexibility, exhibiting a great potential in practical applications.