MX (M = Ge, Sn; X = S, Se) sheets: theoretical prediction of new promising electrode materials for Li ion batteries

Abstract

Exploring a new electrode material is one of the key solutions to the development of lithium ion battery. In this work, we, via density functional theory calculations, explored the interaction of Li with recently synthesized two-dimensional structures, MX (M=Ge, Sn; X=S, Se) sheets. Our studies revealed following results: (1) Li atom can spontaneously and rapidly load to MX sheets, and finally form a stable configuration with the adsorption energies of -1.82, -1.70, -1.76, -1.86 eV for GeS, GeSe, SnS, SnSe sheets, respectively; (2) Activation barriers of Li atom along zigzag direction are about 0.19, 0.26, 0.30, 0.36 eV for GeS, GeSe, SnS, SnSe sheets, respectively, which can be activated at room temperature; (3) At relatively large content, MX sheets still can hold Li atoms strongly with very low adsorption energies, providing an effective ensurence of thermodynamic stability of the electrode materials; (4) The results reveal remarkable average voltages, which are about 1.98, 2.12, 2.69, 2.22 V for GeS, GeSe, SnS, SnSe sheets, respectively; (5) Calculated capacities are about 307, 230, 147, 191 mAh/g for GeS, GeSe, SnS, SnSe sheets, respectively, still larger than those of conventional electrode materials. (6) After lithiation, a semiconductor-to-conductor transition was observed, facilitating the electron movement in MX sheets. All of these properties successfully disclose that MX (M=Ge, Sn; X=S, Se) sheets are potential electrode materials expected to be applied in high-performance lithium ion battery. * Introduction Driven by the enormous demand of modern society, energy storage technology attracts great attentions. 1-4 As one of the most important energy storage technologies, lithium ion battery has been the subject of intense investigations. [5][6][7][8] Owning to the great potential for applications, such as portable electronics, electric vehicle and grid storage, lithium ion battery was fast commercialized. Nevertheless, the application of lithium ion battery was also hindered by the requirement of modern society that needs it with good cycling performance, high storage capacity, high energy density, safety and low cost of production. 9-10 To ameliorate these problems, developments of new advanced electrode materials recently garnered materials scientists' interests. [11][12][13] Two-dimensional (2D) materials have captured a great deal of attention as electrode materials due to their large surface-to-volume ratio, which facilitates fast ion load and large ion occupation. Some experimental and computational reports on the capacity of graphene were notable as they predicted that graphene can exhibit high storage capacity, cyclic stability and superior rate capacity. 14-19 Meanwhile, other 2D materials, such as transition-metal dichalcogenides (MX 2 ), 20-24 transition-metal carbides and carbonitrides (MXenes), 25-29 silicence, 30-33 graphdiyne 34-36 and MnO 2 monolayer, 37 have been studied. These novel 2D structures also displayed remarkable storage capacity, cyclic stability and rate capacity. 20-37 Alth...

Atomic-level understanding of interface interactions in a halloysite nanotubes–PLA nanocomposite

“…That is conrmed by the available experimental data: Al-O-Si, 20,25 Al-OH, 36,37 Si-O-Si, 20,25 -CH 3 , 20,25 -CO 20,25,26 and -COH. 20,25 The results also widen the considerations 25,36,37 about the mechanism of bonding PLA with hydroxylated and syloxane HNT surfaces. Table 2 shows the adsorption energies for the most stable adsorption congurations of LA on the surfaces of the halloysite nanotube.…”

“…This information allows one to supplement the experimental data of a number of studies 25,37 on the participation of the carboxyl and hydroxyl groups of PLA in the mechanism of binding to HNT. In particular, the data in papers 34,36,37 conrm the essential role of terminal hydroxyl groups (-OH) of PLA in the process of bond formation with HNT. In addition, occurring adsorption states of LA on the HNT surface are the most energetically favorable.…”

“…In papers 20,[25][26][27]33,34,36 atomic groups which can participate in bond formation between HNT and PLA were revealed according to FTIR-spectroscopy. As atomic surface groups of HNT involved in the interaction were considered: Si-O-Si, 20,25 Al-O-Si, 20,25 Si-O, 33,36,37 Al-OH, 36,37 and hydroxyl groups (-OH), 20,25 arising on the edge surfaces and defects of HNT surfaces. In papers 34,36,37 the possibility of special role of terminal hydroxyl groups (-OH) of PLA polymer chains, which can form hydrogen bond with HNT, is indicated.…”

“…As atomic surface groups of HNT involved in the interaction were considered: Si-O-Si, 20,25 Al-O-Si, 20,25 Si-O, 33,36,37 Al-OH, 36,37 and hydroxyl groups (-OH), 20,25 arising on the edge surfaces and defects of HNT surfaces. In papers 34,36,37 the possibility of special role of terminal hydroxyl groups (-OH) of PLA polymer chains, which can form hydrogen bond with HNT, is indicated. Interaction of atomic groups -CH 3 , 20,25 -CO 20,25,26 and -COH 20,25 of PLA with HNT row is also possible.…”

A review of shape memory polymers bearing reversible binding groups

“…A number of SMP nanocomposites, where hydrogen bonding plays a pivotal role, have also been reported. [71][72][73][74][75][76] For example, Mendez and coworkers 75 reported on a bioinspired PU nanocomposite containing cotton cellulose nanowhisker (CNW) reinforcements. This system relied on the unique ability of the percolated CNW network to disassemble when in the presence of water, but later reforms the percolated network when the solvent is removed.…”