A cation-dipole-reinforced elastic polymer electrolyte enabling long-cycling quasi-solid-state lithium metal batteries

The application of ionic liquids(IL)in polymer electrolytes represents a safer alternative to the currently used organic solvents in lithium batteries due to their nonflammability and thermal stability.However,as a plasticizer,it is generally agreed that the introduction of ionic liquid usually leads to a trade-off between ion transport and mechanical properties of polymer electrolyte.Here we report the synthesis of an IL-embedded polymer electrolyte with both high ionic conductivity(2.77×10^(-4)S cm^(-1)at room temperature)and excellent mechanical properties(high tensile strength up to 11.4 MPa and excellent stretchability of 387%elongation at break)achieved by strong ion–dipole interactions between polymer electrolyte components,which was unveiled by the DFT calculation.Moreover,this polymer electrolyte also exhibits nonflammability,good thermal stability and the ability to recover reversibly from applied stress,i.e.,excellent elasticity.This highly viscoelastic polymer electrolyte enables tight interfacial contact and good adaptability with electrodes for stable lithium stripping/plating for 2000 h under a current density of 0.1 mA cm^(-2).By coupling with this polymer electrolyte,the LiFePO_(4)/Li cells exhibit outstanding cycling stability at room temperature as well as the reliability under extreme environmental temperature or being abused.

Vibration of quadrilateral embedded multilayered graphene sheets based on nonlocal continuum models using the Galerkin method

Free vibration analysis of quadrilateral multilayered graphene sheets（MLGS） embedded in polymer matrix is carried out employing nonlocal continuum mechanics.The principle of virtual work is employed to derive the equations of motion.The Galerkin method in conjunction with the natural coordinates of the nanoplate is used as a basis for the analysis.The dependence of small scale effect on thickness,elastic modulus,polymer matrix stiffness and interaction coefficient between two adjacent sheets is illustrated.The non-dimensional natural frequencies of skew,rhombic,trapezoidal and rectangular MLGS are obtained with various geometrical parameters and mode numbers taken into account,and for each case the effects of the small length scale are investigated.

DLM/FD SIMULATION OF CHANNEL FLOW WITH FENE POLYMER CHAIN SUSPENSION

Distributed Lagrange Multiplier/Fictitious Domain （DLM/FD） method was employed to simulate the channel flow with polymer suspension. The polymer molecules were modeled as Finitely Extensible Nonlinear Elastic （FENE） chains and FENE chain cluster. The coiled stretched transition of FENE chains was examined and the change in configuration of FENE chains was presented. The average velocity profile of the fully developed channel flow with 64 FENE chains was given and fitted well with the power-law curve. The change of chain cluster configuration was also simulated. These simulations show that DLM/FD method is capable of simulating the motion of not only FENE chain, but also FENE chain cluster.

Intramolecular hydrogen bonds in a single macromolecule:Strength in high vacuum versus liquid environments

As a weak non-covalent interaction,hydrogen bond(H-bond)is highly susceptible to the environmental interference.However,the direct quantification of a single H-bond under an interference-free condition is still a challenge.Herein,the intramolecular H-bond in a model system,poly(N-isopropylacrylamide),is studied in high vacuum by single-molecule atomic force microscopy and steered molecular dynamics simulations,which allows the precise quantification of H-bond strength in an interference-free state.Control experiments show that the H-bond is significantly weakened in nonpolar solvent,even if the dielectric constant is very close to vacuum.If a polar solvent is used as the environment,the H-bond will be further weaker or even broken.These results imply that for experiments in any liquid environment,the H-bond strength(△G)will be only -50% or even less of that measured in vacuum.Further analysis shows that in liquid environments,AG decays in a quasi-linear way with the increase of the dielectric constant(ε).For H-bond studies in future,the result measured in vacuum can be set as the standard value,namely,the inherent strength.This approach will provide fundamental insights into the H-bond participated nano-structures and materials in different environments.