The fabrication of nanopores in atomically thin graphene has recently been achieved, and translocation of DNA has been demonstrated. Taken together with an earlier proposal to use graphene nanogaps for the purpose of DNA sequencing, this approach can resolve the technical problem of achieving single-base resolution in electronic nucleobase detection. We have theoretically evaluated the performance of a graphene nanogap setup for the purpose of whole-genome sequencing, by employing density functional theory and the nonequilibrium Green's function method to investigate the transverse conductance properties of nucleotides inside the gap. In particular, we determined the electrical tunneling current variation at finite bias due to changes in the nucleotides orientation and lateral position. Although the resulting tunneling current is found to fluctuate over several orders of magnitude, a distinction between the four DNA bases appears possible, thus ranking the approach promising for rapid whole-genome sequencing applications.

Identifying a suitable electrode material with desirable electrochemical properties remains a primary challenge for rechargeable Al-ion batteries. Recently an ultrafast rechargeable Al-ion battery was reported with high charge/discharge rate, (relatively) high discharge voltage and high capacity that uses a graphite-based cathode. Using calculations from first-principles, we have investigated the staging mechanism of AlCl intercalation into bulk graphite and evaluated the stability, specific capacity and voltage profile of AlCl intercalated compounds. Ab initio molecular dynamics is performed to investigate the thermal stability of AlCl intercalated graphite structures. Our voltage profiles show that the first AlCl intercalation step could be a more sluggish step than the successive intercalation steps. However, the diffusion of AlCl is very fast in the expanded graphite host layers with a diffusion barrier of ∼0.01 eV, which justifies the ultrafast charging rate of a graphite based Al-ion battery. And such an AlCl intercalated battery provides an average voltage of 2.01-2.3 V with a maximum specific capacity of 69.62 mA h g, which is excellent for anion intercalated batteries. Our density of states and Bader charge analysis shows that the AlCl intercalation into the bulk graphite is a charging process. Hence, we believe that our present study will be helpful in understanding the staging mechanism of AlCl intercalation into graphite-like layered electrodes for Al-ion batteries, thus encouraging further experimental work.

Graphite dual-ion batteries represent a potential battery concept for large-scale stationary storage of electricity, especially when constructed free of lithium and other chemical elements with limited natural reserves. Owing to their non-rocking-chair operation mechanism, however, the practical deployment of graphite dual-ion batteries is inherently limited by the need for large quantities of electrolyte solutions as reservoirs of all ions that are needed for complete charge and discharge of the electrodes. Thus far, lithium-free graphite dual-ion batteries have employed moderately concentrated electrolyte solutions (0.3–1 M), resulting in rather low cell-level energy densities of 20–70 Wh kg−1. In this work, we present a lithium-free graphite dual-ion battery utilizing a highly concentrated electrolyte solution of 5 M potassium bis(fluorosulfonyl)imide in alkyl carbonates. The resultant battery offers an energy density of 207 Wh kg−1, along with a high energy efficiency of 89% and an average discharge voltage of 4.7 V.

Graphene nanogaps and nanopores show potential for the purpose of electrical DNA sequencing, in particular because single-base resolution appears to be readily achievable. Here, we evaluated from first principles the advantages of a nanogap setup with functionalized graphene edges. To this end, we employed density functional theory and the non-equilibrium Green's function method to investigate the transverse conductance properties of the four nucleotides occurring in DNA when located between the opposing functionalized graphene electrodes. In particular, we determined the electrical tunneling current variation as a function of * To whom correspondence should be addressed † Uppsala University ‡ Nakhon Phanom University ¶ Royal Institute of Technology the applied bias and the associated differential conductance at a voltage which appears suitable to distinguish between the four nucleotides. Intriguingly, we observe for one of the nucleotides a negative differential resistance effect.

stable CdS monolayer sheets are proposed using the state-of-the-art theoretical calculations. Three different conformers (planar, distorted, and buckled) are predicted which are separated by low energy barriers. These monolayer sheets are not only thermodynamically, mechanically, and dynamically stable but also can withstand temperature as high as 1000 K. Band edge alignment of these monolayer sheets and bulk CdS is done with respect to the water oxidation and reduction potential to evaluate their photocatalytic activities. Here we show a planar CdS monolayer sheet is the most promising material for visible light photocatalysis and can be used for electronic and optoelectronic devices.

Cardanol, an agrowaste – solventless synthesis and processability of benzoxazine monomers. Tailoring the polymer properties as a function of oxazine functionality in the monomers.

In this work, an octahedral-shaped iron nanocluster (NC) electrocatalyst has been modeled to examine the pathways of electrochemical nitrogen reduction reaction (NRR) and analyze the catalytic activity over the (110) surface. The Heyrovsky-type associative and dissociative NRR mechanisms on the (110) facet and edge of the NC are systematically elucidated by calculating reaction free energies for all the possible elementary reaction steps in NRR. Our results show that the most of the NRR intermediates (*N 2 , *N 2 H, *N 2 H 2 , *N, *NH, *NH 2 , and *NH 3 ) bind weakly on different sites of the NC in comparison to that on the periodic Fe(110) surface. Importantly, the reaction free energy change for the potential determining step (PDS) in the distal associative mechanism with the formation of *NNH on the NC facet is lower than the edge of NC and periodic Fe(110) surface. Our study also indicates that the PDS (*NH 2 formation) associated with the periodic Fe(110) surface is no longer the same as the reaction is catalyzed by the NC. The calculated value of working potential is observed lower for Fe 85 NC in comparison to that of the periodic Fe(110) surface. Furthermore, the current density plot indicates that the NC shows less hydrogen evolution reaction (HER) activity compared to other considered Fe based systems. Apart from the working potential study, the positive shift of dissolution potential has also been considered for dissolution behavior of Fe from the NC with respect to surface, confirming its stability in an electrochemical environment. The Fe 85 NC electrocatalyst possess quite a low overpotential of 0.29 V for NRR with reduced HER activity, which is further lower compared to that of the well-established Re(111) and enhanced stability toward Fe dissolution in comparison to that of the periodic Fe(110) surface. Therefore, such an NC system may perform as an efficient catalyst for an electrochemical NRR.

Presently, great attention is being directed toward the development of promising electrode materials for non-lithium rechargeable batteries which have the advantages of low cost, high energy storage density, and high rate capacity for substantial renewable energy applications. In this study, we have predicted that the C 3 N monolayer is a potential electrode material for Na-and K-ion batteries by firstprinciple calculations. The diffusion barriers are calculated to be as small as 0.03 eV for Na and 0.07 eV for K, which could lead to a very fast diffusion on the C 3 N monolayer surface, implying high mobility and cycle stability for batteries. The C 3 N monolayer is predicted to allow a high storage capacity of 1072 mAh/g by the inclusion of multilayer adsorption with an average voltage of 0.13 V for Na 2 C 3 N and 0.26 V for K 2 C 3 N systems, which is more promising than previously studied anode materials. All of these results ensure that the C 3 N monolayer could serve as an excellent anode material for Na-and K-ion batteries.