Lithium Polysulfide Interaction with Group III Atoms-Doped Graphene: A Computational Insight

Abstract

The development of long lifetime Li–S batteries requires new sulfur–carbon based composite materials that are able to suppress the shuttle effect—namely, the migration of soluble lithium polysulfides from the cathode to the anode of the cell. Graphene is one of the most promising carbon supports for sulfur, thanks to its excellent conductivity and to the possibility of tailoring its chemical–physical properties, introducing heteroatoms in its structure. By using first principle density functional theory simulations, this work aims at studying the effect of doping graphene with group III elements (B, Al, Ga) on its electronic properties and on its chemical affinity towards lithium polysulfides. Our results show that Al and Ga doping strongly modify the local structure of the lattice near heteroatom site and generate a charge transfer between the dopant and its nearest neighbor carbon atoms. This effect makes the substrate more polar and greatly enhances the adsorption energy of polysulfides. Our results suggest that Al- and Ga-doped graphene could be used to prepare cathodes for Li–S cells with improved performances and lifetime.

The Effects of Random Porosities in Resonant Frequencies of Graphene Based on the Monte Carlo Stochastic Finite Element Model

“…Graphene is a two-dimensional (2D) nanomaterial composed of a hexagonal honeycomb lattice [ 1 ]. With the distinguished properties in electronics, thermal conductivity, optical transparence and mechanics, graphene has powerful potential in nanosensors, nano-resonators, supercapacitors [ 2 , 3 , 4 ], batteries [ 5 , 6 , 7 ], etc. The covalent bonds between carbon atoms in graphene ensure the stability in mechanical and chemical properties [ 8 , 9 , 10 , 11 ].…”

Understanding the role of lithium bonds in doped graphene nanoribbons as cathode hosts for Li‐S batteries: A first‐principles study

“…The delocalized π system located in C atoms becomes strengthened due to additional electrons transferred from B atom in the BO‐GNR. Hence, the carbon atoms surrounding the B atom become more active and the substrate becomes more polar causing a more favorable condition for Li 2 S adsorption 22,44 . Hence, it is advantageous to co‐dope GNR with atoms having less electronegativity than carbon along with atoms like oxygen to achieve strong adsorption 45 …”

The Fingerprints of Resonant Frequency for Atomic Vacancy Defect Identification in Graphene

“…The geometrical parameters involving the length of carbon covalent bonds and the diameter of the cross-section of the beam (thickness of graphene) are 0.27 nm and 0.032 nm, respectively. The material properties, namely Young's modulus, Poisson's ratio, and mass density, are settled as 1.2 TPa, 0.2, and 2700 Kg/m 3 , respectively, according to the reported literature [7,[28][29][30].…”

“…In addition, the Block Lanczos extraction method is used in this work for its efficiency in large symmetric eigenvalue problems [7]. As the involved matrix for the finite element computation of resonant frequencies are sparse and large, the Block Lanczos extraction method is competitive when compared with other methods [28].…”

“…Defects are recognized as the unpredictable and stochastic existence in the lattice of graphene, which seriously compromises the expected performances and properties [1,2]. However, defects also play positive roles by intentionally tailoring the chemical and physical properties, which present promising potentials in a wide range of applications, such as catalysis [3,4], hydrogen storage [5,6], batteries [7,8], and sensors [9,10]. With the current experimental conditions and manufacturing technologies, defects in graphene are unavoidable during growth and production.…”