Sharif Digital Repository

Formation of unstable solid electrolyte interphase (SEI) layers lacking of thermal stability in non-aqueous electrolytes of rechargeable batteries is the main bottleneck for their long-life cycling, especially at elevated temperatures. Inclusion of a small dose of functional electrolyte additives into the batteries' electrolyte can be highly beneficial to surmount this issue. Of these additives, vinylene carbonate (VC) has drawn particular attention thanks to its high ability to build protective layers at anodes showing good integrity and outstanding thermal stability. In addition to its primary roles in present-day lithium-ion batteries (LIBs), VC additive has also been examined in other... 

Cubic phase Li7La3Zr2O12 (LLZO) is a promising solid electrolyte for next-generation Li-ion batteries. In this work, the combustion sol–gel technique is used to prepare an Al-doped LLZO solid electrolyte. The crystal structure is investigated, and the cubic phase is confirmed. Densification properties were investigated using SEM and optical dilatometry. The densification of the Al-doped sample takes place in two stages through two different shrinkage rates. Using 0.25 mol Al-dopant 94% relative density is achieved at 1100 °C. The effect of Al-doping on electrochemical properties is investigated in detail using AC impedance spectroscopy. The result indicates that the optimum concentration of... 

In Li-ion batteries the interface between the nano-size spherical core graphite and its surrounding solid electrolyte interphase (SEI) layer, just inside SEI is susceptible to damage. Thus, accurate determination of the associated elastic fields is one of the challenges in optimizing the lifetime and capacity of Li-ion batteries. The required precision is achieved by considering the core graphite which belongs to the crystal class D6h as homogeneous spherically isotropic and SEI layer as functionally graded (FG) isotropic material. Moreover, to account for the surface/interface effects appropriately the core-shell nano-structure subjected to the diffusion-induced time-dependent nonuniform...