In the realm of lithium superionic conductors,pursuing higher ionic conductivity is imperative,with the variance in lithium-ion concentration playing a determining role.Due to the permanent and temporary site-blocking...In the realm of lithium superionic conductors,pursuing higher ionic conductivity is imperative,with the variance in lithium-ion concentration playing a determining role.Due to the permanent and temporary site-blocking effects,especially at non-dilute concentrations,not all Li-ions contribute to ionic conductivity.Here,we propose a strategy to directly calculate effective mobile ion concentration in which multiple-ion correlated migration is considered in the percolation analysis with the input of Li-ion distributions and hopping behavior based on kinetic Monte Carlo simulation,termed P-KMC.We provide examples of two representative lithium superionic conductors,cubic garnet-type LixA3B2O12(0≤x≤9;A and B represent different cations)and perovskite-type LixLa2/3−x/3TiO3(0≤x≤0.5),to demonstrate the direct dependence of the ionic conductivity on the effective mobile ion concentration.This methodology provides a robust tool to identify the optimal compositions for the highest ionic conductivity in superionic conductors.展开更多
Few-layer Tellurium, an elementary semiconductor, succeeds most of striking physical properties that black phosphorus(BP) offers and could be feasibly synthesized by simple solution-based methods. It is comprised of n...Few-layer Tellurium, an elementary semiconductor, succeeds most of striking physical properties that black phosphorus(BP) offers and could be feasibly synthesized by simple solution-based methods. It is comprised of non-covalently bound parallel Te chains, among which covalent-like feature appears.This feature is, we believe, another demonstration of the previously found covalent-like quasi-bonding(CLQB) where wavefunction hybridization does occur. The strength of this inter-chain CLQB is comparable with that of intra-chain covalent bonding, leading to closed stability of several Te allotropes. It also introduces a tunable bandgap varying from nearly direct 0.31 eV(bulk) to indirect 1.17 eV(2L) and four(two) complex, highly anisotropic and layer-dependent hole(electron) pockets in the first Brillouin zone.It also exhibits an extraordinarily high hole mobility(~10~5 cm^2/Vs) and strong optical absorption along the non-covalently bound direction, nearly isotropic and layer-dependent optical properties, large ideal strength over 20%, better environmental stability than BP and unusual crossover of force constants for interlayer shear and breathing modes. All these results manifest that the few-layer Te is an extraordinary-high-mobility, high optical absorption, intrinsic-anisotropy, low-cost-fabrication, tunable bandgap, better environmental stability and nearly direct bandgap semiconductor. This ‘‘one-dimen sion-like" few-layer Te, together with other geometrically similar layered materials, may promote the emergence of a new family of layered materials.展开更多
基金supported by the National Natural Science Foundation of China(Nos.92270124,52102313,92472207)the Hunan Provincial Natural Science Foundation of China(No.2023JJ40635)+1 种基金Shandong Province Natural Science Foundation(No.ZR2022ZD11)the High-Performance Computing Center of Shanghai University and Shanghai Engineering Research Center of Intelligent Computing Systems for providing computing resources and technical support.
文摘In the realm of lithium superionic conductors,pursuing higher ionic conductivity is imperative,with the variance in lithium-ion concentration playing a determining role.Due to the permanent and temporary site-blocking effects,especially at non-dilute concentrations,not all Li-ions contribute to ionic conductivity.Here,we propose a strategy to directly calculate effective mobile ion concentration in which multiple-ion correlated migration is considered in the percolation analysis with the input of Li-ion distributions and hopping behavior based on kinetic Monte Carlo simulation,termed P-KMC.We provide examples of two representative lithium superionic conductors,cubic garnet-type LixA3B2O12(0≤x≤9;A and B represent different cations)and perovskite-type LixLa2/3−x/3TiO3(0≤x≤0.5),to demonstrate the direct dependence of the ionic conductivity on the effective mobile ion concentration.This methodology provides a robust tool to identify the optimal compositions for the highest ionic conductivity in superionic conductors.
基金supported by the National Natural Science Foundation of China(11274380,91433103,11622437,61674171,and 61761166009)the Fundamental Research Funds for the Central Universities of China and the Research Funds of Renmin University of China(16XNLQ01)+1 种基金The Hong Kong Polytechnic University(G-SB53)J.Q. and C.W. were supported by the Outstanding Innovative Talents Cultivation Funded Programs 2016 and 2017 of Renmin University of China,respectively
文摘Few-layer Tellurium, an elementary semiconductor, succeeds most of striking physical properties that black phosphorus(BP) offers and could be feasibly synthesized by simple solution-based methods. It is comprised of non-covalently bound parallel Te chains, among which covalent-like feature appears.This feature is, we believe, another demonstration of the previously found covalent-like quasi-bonding(CLQB) where wavefunction hybridization does occur. The strength of this inter-chain CLQB is comparable with that of intra-chain covalent bonding, leading to closed stability of several Te allotropes. It also introduces a tunable bandgap varying from nearly direct 0.31 eV(bulk) to indirect 1.17 eV(2L) and four(two) complex, highly anisotropic and layer-dependent hole(electron) pockets in the first Brillouin zone.It also exhibits an extraordinarily high hole mobility(~10~5 cm^2/Vs) and strong optical absorption along the non-covalently bound direction, nearly isotropic and layer-dependent optical properties, large ideal strength over 20%, better environmental stability than BP and unusual crossover of force constants for interlayer shear and breathing modes. All these results manifest that the few-layer Te is an extraordinary-high-mobility, high optical absorption, intrinsic-anisotropy, low-cost-fabrication, tunable bandgap, better environmental stability and nearly direct bandgap semiconductor. This ‘‘one-dimen sion-like" few-layer Te, together with other geometrically similar layered materials, may promote the emergence of a new family of layered materials.
