Characterizations. Morphological characterization was performed using optical microscopy (Carl Zeiss Microscopy, Germany), SEM (HITACHI SU8010, Japan), and high-resolution TEM (FEI Tecnai G2 F30, USA). O NMR data were obtained on a Bruker Avance 400 MHz NMR spectrometer. 400 μL electrolyte was put into 5 mm NMR tube with 150 μL deuterium oxide (D 2 O) as an external reference in a coaxal insert tube (NORELL).