Exothermal Mechanisms of the battery is occured from the decomposition of the components of the SEI layer that is formed by electrolyte reduction reaction at the interface between electrode and electrolyte. the components of the SEI layer, high temper...
Exothermal Mechanisms of the battery is occured from the decomposition of the components of the SEI layer that is formed by electrolyte reduction reaction at the interface between electrode and electrolyte. the components of the SEI layer, high temperature largely influence on the thermal stability of batteies. Especially the surface modification on the anode using additives in the electrolyte in the battery improves thermal stability and electrochemical behavior at the same time. It is usually studied as an effective method to improve thermal stability and electrochemical behavior. The effect of electrolyte’s composition on the surface chemical and thermal stability of anode materials were studied in this paper .anode materials use soft carbon as carbon and si as non-carbon. The electrolytes used in the experiments were 1 M LiPF6 solutions composed of ethylene carbonate(EC)/ ethylmethylene carbonate (EMC) (30:70 v/v) with VC for P-doped soft carbon anodes and ethylene carbonate (EC)/ diethyl carbonate (DEC) (30:70 v/v) with LiBOB for Si anodes. Attenuated total reflectance Fouriertransform infrared (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) were used to investigate SEI layer of anode materials. It was found that the SEI layer formed in VC & LiBOB-containing electrolyte possessed better properties. The presence of VC in electrolyte brought out the VC-reduced products and decreased the LiF content in SEI layer. The major components of SEI layer. And LiBOB derived –SEI layer is formed lithium oxalate, B2O3.the additive can form a stable anode SEI layer that inhibits electrolyte decomposition. Namely,, The ex situ ATR-FTIR and XPS results for the delithiated anodes, confirmed that the reduction decomposition of electrolyte components is effectively alleviated by the VC & LiBOB-derived SEI and It improve the thermal stability of anodes(soft carbon, Si). The thermal behavior of the fully lithiated anode electrodes (Soft carbon, Si) in contact with an electrolyte is investigated by differential scanning calorimetry (DSC) in the temperature range 40~400°C.
Consequently, It found that the onset temperature of the exothermic reaction of the soft carbon was shifted from 80 °C to 116.56 °C when cycled in the presence of an VC additive. also the onset temperature of the thermal runaway is shifted from 120°C to 250 °C charged LixSi is heated in the presence of LiBOB in the electrolytes,