2020 physisorption analyzer

All of the samples were characterized by scanning electron microscopy (SEM) using a Hitachi S-4800 system and transmission electron microscopy (TEM, JEM-2010F). X-ray diffraction (XRD) measurements were performed with a D8 Bruker diffractormeter with a Cu K_α, (λ = 1.5418 Å) radiation. Raman spectra were recorded with a Bruker spectrometer with 532 nm laser, and X-ray photoelectron spectroscopy (XPS) measurements were carried out using a ESCALab220i-XL electron spectrometer (VG Scientific) using a 300W Al K_α radiation. Nitrogen physisorption was carried out at 77 K with an ASAP 2020 Physisorption Analyzer. The mechanical properties of the prepared hydrogels were investigated using a dynamic mechanical analyzer (DMA Q800).

The morphology and structure of all samples were investigated by FE-SEM (Hitachi S4800) and FE-TEM (FEI Tecnai G2 20 STWIN and Tecnai G2 F20 U-TWIN). Raman spectra were collected using a Renishaw inVia Raman microscope with a laser wavelength of 514.5 nm. XPS measurements were performed on an ESCALAB250Xi apparatus with an Al Kα X-ray source. Before the XPS measurements, the cycled samples were washed repeatedly with fresh dimethyl carbonate to remove the residual electrolyte; in some cases, the cleaned samples were subjected to further washing with 5% HCl to remove most unstable SEI components of the samples if there exist. Nitrogen adsorption/desorption isotherms were measured at 77 K with an ASAP 2020 physisorption analyzer. The Brunauer–Emmett–Teller method and Barrett–Joyner–Halenda model were utilized to estimate the specific surface area and pore size distribution, respectively.