Gel polymer electrolytes(GPEs)present the best compromise between mechanical and electrochemical properties,as well as an improvement of the cell safety in the framework of Li metal batteries production.However,the po...Gel polymer electrolytes(GPEs)present the best compromise between mechanical and electrochemical properties,as well as an improvement of the cell safety in the framework of Li metal batteries production.However,the polymerization mechanism typically employed relies on the presence of an initiator,and is hindered by oxygen,thus impeding the industrial scale-up of the GPEs production.In this work,an UV-mediated thiol-ene polymerization,employing polyethylene glycol diacrylate(PEGDA)as oligomer,was carried out in a liquid electrolyte solution(1M LiTFSI in EC/DEC)to obtain a self-standing GPE.A comparative study between two different thiol-containing crosslinkers(trimethylolpropane tris(3-mercaptopropionate)-T3 and pentaerythritol tetrakis(3-mercaptopropionate)-T4)was carried out,studying the effects of the crosslinking environment and the GPE production methods on the cell performances.All the produced GPEs present an excellent room temperature ionic conductivity above 1 mS cm^(-1),as well as a wide electrochemical stability window up to 4.59 V.When cycled at a current density of C/10 for more than 250 cycles,all of the tested cells showed a stable cycling profile and a specific capacity>100 mAh g^(-1),indicating the suitability of such processes for up-scaling.展开更多
Due to their inherent safety, low cost, and structural stability, TiO2 nanostructures represent a suitable choice as anode materials in sodiumion batteries. In the recent years, various hypotheses have been proposed r...Due to their inherent safety, low cost, and structural stability, TiO2 nanostructures represent a suitable choice as anode materials in sodiumion batteries. In the recent years, various hypotheses have been proposed regarding the actual mechanism of the reversible insertion of sodium ions in the TiO2 structure, and previous reports are often controversial in this respect. Interestingly, when tested as binder- and conducting additive-free electrodes in laboratory-scale sodium cells, amorphous and crystalline （anatase） TiO2 nanotubular arrays obtained by simple anodic oxidation exhibit peculiar and intrinsically different electrochemical responses. In particular, after the initial electrochemical activation, anatase TiO2 shows excellent rate capability and very stable long-term cycling performance with larger specific capacities, and thus a clearly superior response compared with the amorphous counterpart. To obtain deeper insight, the present materials are thoroughly characterized by scanning electron microscopy and ex situ X-ray diffraction, and the insertion of sodium ions in the TiO2 bulk phases is systematically modeled by density functional theory calculations. The present results may contribute to the development of more systematic screening approaches to identify suitable active materials for highly efficient sodium-based energy storage systems.展开更多
基金the project PNRR-NGEU,which has received funding from the MUR-DM 352/2022.
文摘Gel polymer electrolytes(GPEs)present the best compromise between mechanical and electrochemical properties,as well as an improvement of the cell safety in the framework of Li metal batteries production.However,the polymerization mechanism typically employed relies on the presence of an initiator,and is hindered by oxygen,thus impeding the industrial scale-up of the GPEs production.In this work,an UV-mediated thiol-ene polymerization,employing polyethylene glycol diacrylate(PEGDA)as oligomer,was carried out in a liquid electrolyte solution(1M LiTFSI in EC/DEC)to obtain a self-standing GPE.A comparative study between two different thiol-containing crosslinkers(trimethylolpropane tris(3-mercaptopropionate)-T3 and pentaerythritol tetrakis(3-mercaptopropionate)-T4)was carried out,studying the effects of the crosslinking environment and the GPE production methods on the cell performances.All the produced GPEs present an excellent room temperature ionic conductivity above 1 mS cm^(-1),as well as a wide electrochemical stability window up to 4.59 V.When cycled at a current density of C/10 for more than 250 cycles,all of the tested cells showed a stable cycling profile and a specific capacity>100 mAh g^(-1),indicating the suitability of such processes for up-scaling.
文摘Due to their inherent safety, low cost, and structural stability, TiO2 nanostructures represent a suitable choice as anode materials in sodiumion batteries. In the recent years, various hypotheses have been proposed regarding the actual mechanism of the reversible insertion of sodium ions in the TiO2 structure, and previous reports are often controversial in this respect. Interestingly, when tested as binder- and conducting additive-free electrodes in laboratory-scale sodium cells, amorphous and crystalline （anatase） TiO2 nanotubular arrays obtained by simple anodic oxidation exhibit peculiar and intrinsically different electrochemical responses. In particular, after the initial electrochemical activation, anatase TiO2 shows excellent rate capability and very stable long-term cycling performance with larger specific capacities, and thus a clearly superior response compared with the amorphous counterpart. To obtain deeper insight, the present materials are thoroughly characterized by scanning electron microscopy and ex situ X-ray diffraction, and the insertion of sodium ions in the TiO2 bulk phases is systematically modeled by density functional theory calculations. The present results may contribute to the development of more systematic screening approaches to identify suitable active materials for highly efficient sodium-based energy storage systems.
