First Principles Study Of Porous Carbon As Anode Material For Metal-Ion (Na, Li, Mg) Batteries Applications

Abstract

Sodium-ion batteries (SIBs) have been identified as an effective technology for grid-scale energy storage because of relatively low cost and natural abundance of sodium, but the lack of suitable anode materials with high Coulombic efficiency and reversible capacity has been a challenge. While graphite, an anode material in Lithium-ion batteries (LIBs), has been used for storing Na ions, its performance in terms of efficiency and capacity has been unsatisfactory for practical applications. Hard porous carbon has the promise to be an excellent anode in SIBs, but its atomicscale structure is not known to pose a fundamental scientific question that must be addressed to understand the mechanism of its ability to store Na+ ions. Here, we present a computational route to construct structural models of porous forms of carbon. Using first-principles density functional theory simulations we derive the model porous carbon structures of varying density (1.70, 1.85, 2.0 g/cm3 ), and determine their interaction with intercalating Na, Li, and Mg atoms estimating the associated anodic voltages. While Li and Mg interact more strongly with porous carbon than Na ions, we demonstrate that carbon atoms are chemically more activated at a lower density of 1.7 g/cm3 resulting in strong interaction with Na atoms and can be good anodic material in NIBs. Our comparative analysis of changes in the electronic structure of porous carbon with Na, Li, and Mg intercalation helps understand the mechanism of Na uptake into hard and porous carbon and will stimulate the development of improved carbon-based anodic materials for SIBs. All calculations were performed using the Quantum espresso simulation package, the total energy was calculated by the generalized gradient approximation coupled with PBE functional.