MoS₂/Epitaxial graphene layered electrodes for solid-state supercapacitors

Abstract

The potential of transition metal dichalcogenides such as MoS2 for energy storage has been significantly limited so far by the lack of conductivity and structural stability. Employing highly conductive, graphitic materials in combination with transition metal dichalcogenides can address this gap. Here, we explore the use of a layered electrode structure for solid-state supercapacitors, made of MoS2 and epitaxial graphene (EG) on cubic silicon carbide for on-silicon energy storage. We show that the energy storage of the solid-state supercapacitors can be significantly increased by creating layered MoS2/graphene electrodes, yielding a substantial improvement as compared to electrodes using either EG or MoS2 alone. We conclude that the conductivity of EG and the growth morphology of MoS2 on graphene play an enabling role in the successful use of transition metal dichalcogenides for on-chip energy storage.

2D MoS2 Heterostructures on Epitaxial and Self‐Standing Graphene for Energy Storage: From Growth Mechanism to Application

“…Having determined the right growth conditions on epitaxial graphene, we have been able to synthesize samples of MoS 2 vertical sheets grown on graphene sponge to fabricate potassium‐ion capacitors with interesting results, demonstrating the excellent properties of this new heterostructure for energy applications. These results overcome largely the results obtained previously by our group with MoS 2 /graphene/SiC [ 32 ] demonstrating the advantage of using Nano Porous Graphene for his superior conductivity and porosity characteristics.…”

“…[27] CVD starting from MoO 3 and S precursors can be used to grow high-quality MoS 2 heterostructures on several substrates in a scalable way. [9,[28][29][30][31][32][33] Controlling the size, shape, and number of layers of MoS 2 is possible by changing the growth parameters of the CVD reactor; [34] however, the growth depends critically on the interaction with the substrate and a full understanding of this process is still lacking.…”

“…[ 25 ] In our previous work, the capacitance of an electrode made from the heterostructure of MoS 2 and EG on cubic SiC dramatically increased to 554 μFcm −2 in comparison with the values of 2.5, 24 and 32 μFcm −2 for plain SiC/Si, EG and MoS 2 electrodes respectively. [ 32 ]…”

“…[25] In our previous work, the capacitance of an electrode made from the heterostructure of MoS 2 and EG on cubic SiC dramatically increased to 554 μFcm −2 in comparison with the values of 2.5, 24 and 32 μFcm −2 for plain SiC/Si, EG and MoS 2 electrodes respectively. [32] In this work, the growth mechanism of MoS 2 is explored on two different graphene substrates, epitaxial graphene on SiC and self-standing NPG, with the aim of uncovering the role of the substrate on the nucleation, ordering and orientation of the 2D islands. We will compare the CVD growth of MoS 2 on substrates with different surface and subsurface structure: EG on SiC with terrace sizes ranging from 45 nm to 2 μm and selfstanding NPG.…”