Atypical performance of CoO-accelerated interface tweaking in hierarchical cobalt phosphide/oxide@P-doped rGO heterostructures for hybrid supercapacitors

Paulraj Arunkumar; Sampath Gayathri; Dipankar Saha; Jong Hun Han

doi:10.1016/j.jcis.2022.12.055

Atypical performance of CoO-accelerated interface tweaking in hierarchical cobalt phosphide/oxide@P-doped rGO heterostructures for hybrid supercapacitors

J Colloid Interface Sci. 2023 Apr:635:562-577. doi: 10.1016/j.jcis.2022.12.055. Epub 2022 Dec 16.

Authors

Paulraj Arunkumar¹, Sampath Gayathri¹, Dipankar Saha², Jong Hun Han³

Affiliations

¹ School of Chemical Engineering, Chonnam National University, 300, Yongbong-dong, Buk-Gu, Gwangju 61186, South Korea.
² School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom.
³ School of Chemical Engineering, Chonnam National University, 300, Yongbong-dong, Buk-Gu, Gwangju 61186, South Korea. Electronic address: jhhan@chonnam.ac.kr.

PMID: 36610200
DOI: 10.1016/j.jcis.2022.12.055

Abstract

Designing two-dimensional (2D) heterostructures based on suitable energy materials is a promising strategy to achieve high-performance supercapacitors with hybridized transition metal and carbonaceous-based electrodes. The influence of each component and its content on the capacitor performance necessitates deeper insights. In this study, a 2D/2D heterostructure made of hierarchical pseudocapacitive cobalt phosphide/oxide and P-doped reduced graphene oxide (PrGO) nanosheets (CoP/CoO@PrGO) was fabricated using porous zeolitic-imidazolate framework precursor. The decoration of 2D leaf-like CoP/CoO hybrid onto PrGO could create a unique interface with a large number of active sites, CoO-driven creation of pseudocapacitive surface PO_x species, and high P content (∼3 at.%) in PrGO, thus promoting the Faradaic reaction, electrical conductivity, and overall charge storage. This framework yields a high specific capacitance of 405 F g^-1 at 5 A g^-1 and excellent cycling stability (over 100 % after 10,000 cycles), superior to those of pristine CoP@PrGO (300 F g^-1 at 5 A g^-1). Furthermore, the fabricated asymmetric supercapacitor delivers reasonable energy density of 4.2 Wh kg^-1 at a power density of 785 W kg^-1 and cycling stability of ∼100 % after 10,000 cycles. Therefore, CoP/CoO@PrGO with its unique interfacial properties can promote the development of heterostructure electrode for high-performance supercapacitors.

Keywords: Heterostructure; Oxide; Phosphide; Phosphorus-doped rGO; Supercapacitor; Transition metal.