Discovery dsc

The main thermal transition upon melting (T_m) and cooling (T_c) were determined by using a Discovery DSC differential scanning calorimeter (TA Instruments, Singapore, Singapore) at a rate of 2 °C/min from 10 to 60 °C and back to 10 °C. The chamber was kept under a nitrogen environment. The software Trios (TA Instruments) was used to calculate the enthalpy associated with the phase transitions (ΔH_m and ΔH_c). The enthalpy associated with a thermal transformation was determined by integrating the endothermic or exothermic peak areas.

Thermal analysis was performed using a Discovery DSC (TA Instruments, New Castle, DE, USA). Approximately 7–10 mg of each sample was placed in an aluminum Tzero pan and sealed with an aluminum hermetic lid. The samples were cooled down to −30 °C, kept isothermal for two minutes and then heated to 100 °C with a heating rate of 3 °C/min with an underlying modulation amplitude of 1 °C and a period of 50 s. A constant nitrogen flow rate of 50 mL/min was applied. To determine the glass transition temperature (T_g), the data collected were analyzed using Trios software (TA instruments, New Castle, DE, USA). In addition to the mDSC, thermogravimetric analysis was carried out for each sample using the Discovery TGA (TA Instruments, New Castle, DE, USA) in order to determine the residual water content in the samples after freeze-drying. The data were analyzed using the Trios software as well.

Thermal analyses of the starting ingredients and lyophiles were carried out using a Discovery DSC equipped with a refrigerated cooling accessory (TA Instruments, New Castle, DE, USA). Nitrogen (50 mL/min) was used as the purge gas. Samples were weighed (7–12 mg) and hermetically sealed into Tzero pans (TA Instruments, New Castle, DE, USA). To determine the T_g values of the samples, the samples were heated from −20 °C to a temperature 20–30 °C higher than the expected T_g at a rate of 20 °C/min. Samples were then cooled to −20 °C at 10 °C/min, followed by heating to 150 °C at a rate of 20 °C/min. The onset glass transition temperature of the second heating step was reported as T_g unless otherwise stated.
To determine onset T_g’ of the frozen samples prior to lyophilization (for determining effective primary drying temperature during lyophilization), approximately 25 μL of solutions were pipetted into Tzero pans and sealed. Solutions were first cooled to −80 °C and held for 5 min at this temperature before being heated to 0 °C at a rate of 10 °C/min. TRIOS software was used to determine the T_g or T_g’ from the scans (TA Instruments, New Castle, DE, USA).

For DSC measurement, a Discovery DSC (TA Instruments) was used. Aluminum crucibles were filled with PEO powder and a mixture of PEO powder and LiTFSI powder and sealed under an inert atmosphere. To melt the polymer and to dissolve the LiTFSI in the polymer matrix, the components were first heated up to 120 °C with a heating ramp of 10 °C min⁻¹, eliminating the thermal history. In a second heating run, from −80 to 180 °C with a heating ramp of 10 °C min⁻¹, the thermal properties, glass transition temperature (T_g), melting temperature (T_m), and crystallinity (K) were determined for neat-PEO and (PEO)₂₀LiTFSI electrolytes.