Synthesis and characterization of LiBOB as electrolyte for lithium-ion battery

Abstract

A synthesis process of lithium bis(oxalato) borate (LiBOB) has been conducted. LiBOB is one of lithium salts which is potentially viable to be utilized as an electrolyte material for lithium-ion battery. In the synthesis of LiBOB powder, oxalic acid, lithium hydroxide, and boric acid were mixed with 2:1:1 mol ratio until homogeneous. The method employed in the synthesis of LiBOB was solid state reaction. According to the result analysis from a differential thermal analyzer (DTA) equipment, it was decided that the first heat preservation should be carried out at 120 °C for 4 h, and then heating temperature for preparing LiBOB was at 240 °C for 7 h. The crystal structure of the LiBOB powder formed from the heating process was analyzed with X-ray diffractometer (XRD). The data found were further explored to determine the phase formed, to calculate percentage of synthesized LiBOB from the crystallography data. The dominant phases formed were LiBOB and LiBOB hydrate, and impurities in another phase were also presented. The result of Fourier transform infra red (FTIR) spectroscopy within wave number range of 500–4000 cm−1 confirmed that functional group of LiB(C2O4)2 compound was found, identified by the appearance of absorption band C-O, C = O, B-O, O-B-O, and C-C. LiBOB microstructure which was observed with scanning electron microscope (SEM) is also presented. Furthermore, LiBOB powder was made into liquid electrolyte with carbonate-based solvent, and tested in a half-cell lithium-ion battery which is characterized on the cyclic voltammetry (CV) curves.