Facile Self-Assembly of Exfoliated Graphene/PANI Film for High-Energy Zn-Ion Micro-Supercapacitors

Abstract

The Zn-ion micro-supercapacitor (ZMSC) is a promising candidate for developing miniaturized and integrated energy storage devices. To achieve high-performance functional groups with simple processing to composite with rod-like active PANI fibers, we prepared exfoliated graphene (EG) with an appropriate amount of O-containing functional groups. The appropriate O content simultaneously facilitated self-assembly of the EG and PANI fibers and maintained the electric conductivity of the composite, producing a free-standing EG/PANI film without additional conductive additives or current collectors. As an interdigital electrode for the ZMSC, the EG/PANI film showed ultrahigh capacitance of 1.8 F cm−2 at 2.6 mA cm−2 (361.3 F g−1 at 0.5 A g−1) and landmark energy density of 755.8 μWh cm−2 at 2.3 mW cm−2 (148.2 Wh kg−1 at 451.7 W kg−1). The facile preparation of the high-performance EG/PANI electrode provides a potential path for practical applications with ZMSCs.

Recent progress of high-performance in-plane zinc ion hybrid micro-supercapacitors: design, achievements, and challenges

“…5a). 98 Owing to the O-containing functional groups on the EG and the effective dispersion of the rod-like PANI fibers in the 2D graphene layer, the achieved EG/PANI film as the interdigitated electrode of the ZIHMSCs displayed ultrahigh capacitance of 1.8 F cm −2 at 2.6 mA cm −2 and excellent energy density of 755.8 μW h cm −2 at 2.3 mW cm −2 . As another representative example, a flexible ZIHMSC was fabricated by mask-assisted ion sputtering and microelectrode deposition of a PPy/reduced graphene oxide (rGO) hybrid framework cathode and Zn nanosheet anode onto a flexible substrate (Fig.…”

“…99 As a result, the as-fabricated ZIHMSCs composed of LIG@PPy micro-cathode and Zn micro-anode exhibited a wide voltage window (1.7 V) and 200× enhancement in the areal capacitance/energy density as compared to that of the pristine LIG counterpart. 98 Very recently, it has been proved that fluorinated LIG (FLIG) with interconnected porous structure can not only serve as cathode material, but also act as an ideal substrate for the uniform electrodeposition of Zn nanosheets. 100 The as-obtained ZIHMSCs consisting of the FLIG cathode and Zn@FLIG anode delivered more than 15 times enhancement in both the areal capacitance (42.32 vs. 2.73 mF cm −2 ) and energy density (15.1 vs. 0.97 μW h cm −2 ) than the commercial LIG based ZHMSCs (42.32 vs. 2.73 mF cm −2 ), respectively.…”

“…To address this issue, several effective strategies, including integration of graphene with other materials possessing high capacitance and introduction of heteroatom dopants (such as O and F) onto the graphene layer, have been demonstrated in recent years. [98][99][100] For example, a facile method was adopted to construct free-standing ZIHMSCs with good electrical conductivity by the selfassembly of EG/PANI film without additional conductive addi-tives or current collectors (Fig. 5a).…”