We calculated the longitudinal acoustic phonon limited electron mobility of 14 two dimensional semiconductors with composition of MX 2 , where M (= Mo, W, Sn, Hf, Zr and Pt) is the transition metal, and X is S, Se and Te. We treated the scattering matrix by deformation potential approximation. We found that out of the 14 compounds, MoTe 2 , HfSe 2 and HfTe 2 , are promising regarding to the possible high mobility and finite band gap. The phonon limited mobility can be above 2500 cm 2 V −1 s −1 at room temperature.

in order to restrict the loss of material. Furthermore, due to their scalability and flexibility, 3D flexible electronics (see Supporting Information (SI), where Table S1 contains a list) were considered revolutionary materials and were used in many fields such as imperceptible electronic devices, wearable electronic devices, and bionic technology. [11][12][13] Recently studies have shown the encapsulation of sulfur in the pores of carbon materials, such as meso-/microporous carbons, [11] cable-shaped carbon, [12] and carbon nanotubes/fibers, [13] can reduce the capacity fading. However, such nonpolar flexible carbon materials have a destructive disadvantage; they only have physical van der Waals (vdW) adsorption for polar Li 2 S n , which leads to the facile detachment of Li 2 S n from the carbon surface. [14] This proves that carbon-based materials alone cannot serve as the perfect host. In light of this new insight, various types of polar functional groups on carbon-based materials have been demonstrated to increase the interaction between Li 2 S n species and the electrode; these materials can generally be categorized into three types: polymers (polyaniline, polypyrrole, poly(3,4ethylenedioxythiophene) (PEDOT)), [15] metal oxides

Owing to the high theoretical specific capacity (1166 mAh g), lithium sulfide (LiS) has been considered as a promising cathode material for Li-S batteries. However, the polysulfide dissolution and low electronic conductivity of LiS limit its further application in next-generation Li-S batteries. In this report, a nanoporous LiS@C-Co-N cathode is synthesized by liquid infiltration-evaporation of ultrafine LiS nanoparticles into graphitic carbon co-doped with cobalt and nitrogen (C-Co-N) derived from metal-organic frameworks. The obtained LiS@C-Co-N architecture remarkably immobilizes LiS within the cathode structure through physical and chemical molecular interactions. Owing to the synergistic interactions between C-Co-N and LiS nanoparticles, the LiS@C-Co-N composite delivers a reversible capacity of 1155.3 (99.1% of theoretical value) at the initial cycle and 929.6 mAh g after 300 cycles, with nearly 100% Coulombic efficiency and a capacity fading of 0.06% per cycle. It exhibits excellent rate capacities of 950.6, 898.8, and 604.1 mAh g at 1C, 2C, and 4C, respectively. Such a cathode structure is promising for practical applications in high-performance Li-S batteries.

Three-dimensional aerogel with ultrathin tellurium nanowires (TeNWs) wrapped homogeneously by reduced graphene oxide (rGO) is realized via a facile hydrothermal method. Featured with high conductivity and large flexibility, the rGO constructs a conductive three-dimensional (3D) backbone with rich porosity and leads to a free-standing, binder-free cathode for lithium-tellurium (Li-Te) batteries with excellent electrochemical performances. The cathode shows a high initial capacity of 2611 mAh cm(-3) at 0.2 C, a high retention of 88% after 200 cycles, and a high-rate capacity of 1083 mAh cm(-3) at 10 C. In particular, the 3D aerogel cathode delivers a capacity of 1685 mAh cm(-3) at 1 C after 500 cycles, showing pronounced long-cycle performance at high current density. The performances are attributed to the well-defined flexible 3D architecture with high porosity and conductivity network, which offers highly efficient channels for electron transfer and ionic diffusion while compromising volume expansion of Te in charge/discharge. Owing to such advantageous properties, the reported 3D rGO/tellurium nanowire (3DGT) aerogel presents promising application potentials as a high-performance cathode for Li-Te batteries.