Nanoporous-Carbon as a Potential Host Material for Reversible Mg Ion Intercalation

• Published in: Journal of the Electrochemical Society Vol. 163; no. 6; pp. A1030 - A1035
• Main Authors: Siegal, Michael P., Yelton, W. Graham, Perdue, Brian R., Gallis, Dorina F. Sava, Schwarz, Haiqing L.
• Format: Journal Article
• Language: English
• Published: United States The Electrochemical Society 01.01.2016
• Subjects: 30 DIRECT ENERGY CONVERSION; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/2.0851606jes

We study nanoporous-carbon (NPC) grown via pulsed laser deposition (PLD) as an electrically conductive anode host material for Mg2+ intercalation. NPC has high surface area, and an open, accessible pore structure tunable via mass density that can improve diffusion. We fabricate 2032 coin cells using NPC coated stainless-steel disk anodes, metallic Mg cathodes, and a Grignard-based electrolyte. NPC mass density is controlled during growth, ranging from 0.06-1.3 g/cm3. The specific surface area of NPC increases linearly from 1,000 to 1,700 m2/g as mass density decreases from 1.3 to 0.26 g/cm3, however, the surface area falls off dramatically at lower mass densities, implying a lack of mechanical integrity in such nanostructures. These structural characterizations correlate directly with coin cell electrochemical measurements. In particular, cyclic voltammetry (CV) scans for NPC with density ∼0.5 g/cm3 and BET surface area ∼1500 m2/g infer the possibility of reversible Mg-ion intercalation. Higher density NPC yields capacitive behavior, most likely resulting from the smaller interplanar spacings between graphene sheet fragments and tighter domain boundaries; lower density NPC results in asymmetrical CV scans, consistent with the likely structural degradation resulting from mass transport through soft, low-density carbon materials.