3D Printed Graphene Based Energy Storage Devices

Abstract

3D printing technology provides a unique platform for rapid prototyping of numerous applications due to its ability to produce low cost 3D printed platforms. Herein, a graphene-based polylactic acid filament (graphene/PLA) has been 3D printed to fabricate a range of 3D disc electrode (3DE) configurations using a conventional RepRap fused deposition moulding (FDM) 3D printer, which requires no further modification/ex-situ curing step. To provide proof-of-concept, these 3D printed electrode architectures are characterised both electrochemically and physicochemically and are advantageously applied as freestanding anodes within Li-ion batteries and as solid-state supercapacitors. These freestanding anodes neglect the requirement for a current collector, thus offering a simplistic and cheaper alternative to traditional Li-ion based setups. Additionally, the ability of these devices' to electrochemically produce hydrogen via the hydrogen evolution reaction (HER) as an alternative to currently utilised platinum based electrodes (with in electrolysers) is also performed. The 3DE demonstrates an unexpectedly high catalytic activity towards the HER (-0.46 V vs. SCE) upon the 1000th cycle, such potential is the closest observed to the desired value of platinum at (-0.25 V vs. SCE). We subsequently suggest that 3D printing of graphene-based conductive filaments allows for the simple fabrication of energy storage devices with bespoke and conceptual designs to be realised.

Figure 1

Optical images of the 3D printable graphene/PLA (A), the 3D printing process (B) and a variety of printed 3DEs used throughout this study (C). Corresponding SEM (D), Raman (E) and XPS analysis of the printed 3DE are also presented.

Figure 2

Cyclic voltammetric (vs. SCE) analyses over a range of scan rates (5–200 mV s⁻¹) of the graphene/PLA filament and printed 3DE within a 1 mM hexaammineruthenium (III) chloride/0.1 M KCl (A and B respectively) and 1 mM ammonium iron (II) sulfate/0.2 M HClO₄ (C and D respectively). Inset of C is the cyclic voltammetric response from a blank 0.2 M HClO₄ solution utilising the graphene/PLA filament.

Figure 3

Schematic of the coin cell fabrication (A), charge–discharge profiles (B), cycling properties (C), coulombic efficiency (D) and rate capability of the 3D printed anode (E).

Figure 4

Cyclic voltammetry (A) of the 3D-SC consisting of a 2 mm layer of solid electrolyte of PVA and 1.0 M H₂SO₄. Corresponding charge/discharge curves with (C) and without (B) the Kampouris’ circuit in parallel are also presented. Scan Rate: 25 mV s⁻¹. Inset to A is a schematic of the 3D-SC utilised throughout this study.

Figure 5

Comparative linear sweep voltammograms (LSV) (A) using 3DE compared to EPPGE, GCE, BDDE and platinum showing the onset of the HER. Stability studies of the 3DEs (B) using LSV for the initial, 10^th, 100^th and 1000^th scans. Scan rate: 25 mV s⁻¹ (vs. SCE). Note: 3DE_N = 1 is upon the initial scan and 3DE_N = 1000 is upon the 1000^th scan.