The major challenges faced by candidate electrode materials in lithium‐ion batteries (LIBs) include their low electronic and ionic conductivities. 2D van der Waals materials with good electronic conductivity and weak interlayer interaction have been intensively studied in the electrochemical processes involving ion migrations. In particular, molybdenum ditelluride (MoTe2) has emerged as a new material for energy storage applications. Though 2H‐MoTe2 with hexagonal semiconducting phase is expected to facilitate more efficient ion insertion/deinsertion than the monoclinic semi‐metallic phase, its application as an anode in LIB has been elusive. Here, 2H‐MoTe2, prepared by a solid‐state synthesis route, has been employed as an efficient anode with remarkable Li+ storage capacity. The as‐prepared 2H‐MoTe2 electrodes exhibit an initial specific capacity of 432 mAh g−1 and retain a high reversible specific capacity of 291 mAh g−1 after 260 cycles at 1.0 A g−1. Further, a full‐cell prototype is demonstrated by using 2H‐MoTe2 anode with lithium cobalt oxide cathode, showing a high energy density of 454 Wh kg−1 (based on the MoTe2 mass) and capacity retention of 80% over 100 cycles. Synchrotron‐based in situ X‐ray absorption near‐edge structures have revealed the unique lithium reaction pathway and storage mechanism, which is supported by density functional theory based calculations.

It is well known that a nuclear reactor generates various fission products including radioactive fission gases made of isotopes of Xe and Kr. The separation of Xe and Kr isotopes and their entrapment are important tasks for efficient operation of nuclear reactors and fuel-reprocessing plants. Two-dimensional materials are known to have a large surface-to-volume ratio; this makes them prospective candidates as gas adsorbent materials. Motivated by this, we carry out ab initio density functional theorybased calculations to explore the reactivity and selectivity of a monolayer of pristine and 3d transition metal (TM)-functionalized MoS 2 toward the fission gas atoms Xe and Kr. To this end, we first study and analyze the adsorption of the TM adatoms on the monolayer of MoS 2 at different inequivalent crystallographic sites. Further, we calculate partial atomic charges and atom-projected density of states of the functionalized composite systems to understand the bonding mechanism of TM adatoms with the monolayer of MoS 2 . We predict the coexistence of both ionic and covalent bonding between the TM atoms and the surface atoms. Subsequently, we probe the adsorption of Xe and Kr atoms on both the pristine and the TM-functionalized MoS 2 surfaces. Our calculated results indicate that the adsorption energies for Xe (Kr) gas atoms on the functionalized MoS 2 are enhanced up to a maximum of 2.77 (2.86) times of adsorption energy found in case of the pristine surface. We find that the adsorption energy of Xe and Kr gas atoms over different TM atom-functionalized MoS 2 follows the order Ti > V > Co > Ni > Fe > Sc > Mn > Cr > Cu. Charge density difference analyses indicate that the polarization of Xe/Kr adatoms is enhanced in the case of functionalized surfaces, which leads to the strengthened interaction between the noble gas (NG) atoms and the functionalized surfaces, compared to the adsorption of NG on the pristine MoS 2 surface. This polarization has direct one-to-one correspondence with the adsorption energy of these gas atoms on the surface. Moreover, our calculated results suggest that both the pristine and the functionalized MoS 2 surfaces show selectivity for Xe atom over Kr atom. The present study predicts that the TM atom-functionalized MoS 2 surfaces may have great potential for adsorption and selective separation of Xe and Kr atoms, which may have important implication in the field of spent nuclear fuel management.

Fast charging battery materials are of incredible interest to the industry as well as in academia. To enhance the fast charging capabilities of batteries, anode materials must have fast Li-ion diffusion and reaction kinetics. The inherent high electronic conductivity and volumetric energy density of semimetallic 1T′-MoTe 2 are advantageous as a high-rate anode material for lithiumion batteries (LIBs). The high mass density of MoTe 2 helps to decrease the electrode thickness, thus requiring less electrolyte infiltration favoring a reduction in the auxiliary material and electrolyte costs and indirectly increasing the energy density of the cell. Here, a pristine 1T′-MoTe 2 material prepared by a facile and efficient solid-state synthesis route without any addition of carbonaceous additives or surface modifications delivered an initial specific capacity of 538 mAh g −1 with a capacity retention of 92% at 1 A g −1 along with a Coulombic efficiency of 99% over 200 cycles. Ex situ X-ray absorption near-edge structure (XANES) was performed to elucidate the lithium storage mechanism of the 1T′-MoTe 2 anode, which was further complemented by lithiation/ delithiation calculations performed using density functional theory. Furthermore, the 1T′-MoTe 2 //LiCoO 2 full cell exhibited a reversible specific capacity of 388 mAh g −1 at 100 mA g −1 with a Coulombic efficiency of 96% over 100 cycles, which indicates its potential in fast charging battery cells.

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A bandgap bowing parameter of 0.4 ± 0.2 eV for β-(AlxGa1−x)2O3 alloys, with Al compositions (x) up to 0.35, has been determined from the bandgap obtained from low temperature optical reflectivity, which suppresses the effect of electron–phonon interaction on the bandgap. A length scale of inhomogeneity of 0.21 ± 0.03 times of the electron–hole mean free path length has been estimated for β-(AlxGa1−x)2O3 alloys. The unit cell of β-(AlxGa1−x)2O3 alloys compresses, and the lattice parameters vary linearly with Al substitution. Our results provide insight into bandgap engineering and alloy disorder for β-(AlxGa1−x)2O3 alloys, which are an important material system for applications in deep ultraviolet opto-electronic devices.