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

doi:10.1002/smll.201906458

Phosphorus Regulated Cobalt Oxide@Nitrogen-Doped Carbon Nanowires for Flexible Quasi-Solid-State Supercapacitors

Small. 2020 Jan;16(4):e1906458. doi: 10.1002/smll.201906458. Epub 2020 Jan 1.

Authors

Shude Liu¹, Ying Yin^{1

2}, Yang Shen³, Kwan San Hui⁴, Young Tea Chun⁵, Jong Min Kim⁵, Kwun Nam Hui⁶, Lipeng Zhang³, Seong Chan Jun¹

Affiliations

¹ School of Mechanical Engineering, Yonsei University, Seoul, 120749, South Korea.
² Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology, Guilin, 541000, P. R. China.
³ College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100000, P. R. China.
⁴ School of Engineering, University of East Anglia, Norwich, 34668, UK.
⁵ Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, 01223, UK.
⁶ Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macau, 999078, P. R. China.

PMID: 31894633
DOI: 10.1002/smll.201906458

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 Co₃ O₄ (P-Co₃ O₄ ) 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-Co₃ O₄ @P, N-C could reduce the adsorption energy of OH^- and regulate the electrical properties. Accordingly, the P-Co₃ O₄ @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-Co₃ O₄ @P, N-C, Co@P, N-C is simultaneously developed, which can be integrated with P-Co₃ O₄ @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.

Keywords: anion regulation; encapsulated hybrids; flexible quasi-solid-state supercapacitors; in situ structural reconstruction; orientated metal organic frameworks.

Abstract

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