Applied Materials Today 9 (2017) 333–340 Contents lists available at ScienceDirect Applied Materials Today j ourna l h o mepage: www.elsevier.com/locate/apmt Beryllium doped graphene as an efficient anode material for lithium-ion batteries with significantly huge capacity: A DFT study Saif Ullah a,∗ , Pablo A. Denis b , Fernando Sato a a Departamento de Física, Instituto de Ciências Exatas, Campus Universitário, Universidade Federal de Juiz de Fora, 36036-900 Juiz de Fora, MG, Brazil b Computational Nanotechnology, DETEMA, Facultad de Química, UDELAR, CC 1157, 11800 Montevideo, Uruguay a r t i c l e i n f o Article history: Received 12 May 2017 Received in revised form 28 August 2017 Accepted 29 August 2017 Keywords: LIBs Be doping Li adsorption Storage capacity Lithiation potential Density functional calculations a b s t r a c t First-principles density functional theory (DFT) calculations were performed to investigate the lithium (Li) adsorption upon beryllium (Be) doped graphene. Be acts as hole doping in graphene leaving the structure as electron deficient, offering a greater tendency for Li adsorption than in pristine and boron (B) doped graphene. The introduction of Be augments the adsorption energy of Li from -1.11 to -2.53 eV/Li. Furthermore, 12, and 16 Li ions can easily be captured by one Be center in the single and double vacancy case, respectively, with the adsorption energies of -1.33 eV/Li (for both the cases), showing that Be doped graphene is an excellent anode material for lithium ion batteries (LIBs). Consequently, the presence of structural defects, in particular, a divacancy is found to be more efficient in terms of Li storage capacity. A huge Li storage capacity (2303.295 mAh/g) is calculated for Li 8 BeC 7 having reasonable adsorption energy (-1.47 eV/Li). Our calculated capacity is 6.19 times greater than that of the graphite. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Lithium ion batteries (LIBs), which have been extensively used in cellular phones, camcorders, laptop computers and wearable devices, and are also a prospective nominee for hybrid electric cars by virtue of their size and exceptional performance [1]. The most commonly used anode material for LIBs is graphite [2,3]. Unfortunately, the limited lithium (Li) storage capacity of graphite (372 mAh/g) makes it a less desirable candidate for LIBs. A suit- able anode material is the one, which offers the higher adsorption capacity and easily diffusion of Li on anode material. Carbon nano- tubes (CNTs) have the possibilities to adsorb the Li, both inside and on the outside surfaces. For this reason, single-walled CNTs (SWCNTs) have been investigated experimentally, which revealed a higher reversible capacity (as compared to graphite) of 500 mAh/g [4]. Moreover, the chemical etching [5], and ball-milling [6] tech- niques offer the possibility of synthesizing Li 2.7 C 6 CNTs, exhibiting a much higher Li capacity of up to 1000 mAh/g. Due to the exceptional properties of graphene, such as high thermal and electrical conduc- tivities, large surface area, outstanding mechanical strength and wide-ranging electrochemical window, makes it a potential and alternative candidate for its use as anode material in LIBs [7–12]. ∗ Corresponding author. E-mail address: sullah@fisica.ufjf.br (S. Ullah). Unfortunately, there are some issues related to the use of graphene as an anode material. Regardless of the Li concentra- tion upon graphene, the Li atoms are likely to form clusters which can lead to the dendrite formation, resulting in a serious reduction in the charge/discharge capacity of the battery/batteries [13–15]. The Li adsorption energy upon graphene is weaker than the Li–Li interaction, which is the main reason for Li-clusters formation. To avoid Li-clusters formation, the adsorption energy of Li on graphene should exceed the cohesive energy of the bulk Li. Fortunately, there are certain techniques which can address these issues. Few of them include the modification of the graphene surface [16], edge [17], point defects [18], grain boundary [19], doping and complimentary synergy effects [20–26]. However, sub- stitutional doping is the easier and efficient way to enhance the Li adsorption on graphene. The dopants can seriously alter the mag- netic [27,28], thermal [29], electronic [30–32], mechanical [30] and transport properties [30,33] as well as the chemical reactivity of graphene [23,34–41], thus increasing the novelty of these graphene systems regarding to their applications. The most frequently studied dopants are B and N in graphene, which are the neighbors of C atom. B acts as hole doping (p-type) while N as electron doping (n-type) in graphene. These dopants can alter the electronic structure of graphene by lifting (N) or low- ering (B) the Fermi level in the conduction and valence bands, respectively. Regarding the concentration of N doping in graphene and its applications in oxygen reduction reaction and fuel cell http://dx.doi.org/10.1016/j.apmt.2017.08.013 2352-9407/© 2017 Elsevier Ltd. All rights reserved.