Development of boron containing electrolyte additive for lithium ion batteries

With the increase in the use of portable electrical devices, efforts to store energy in low volume and mass are gaining momentum. In this regard, lithium-ion batteries stand out from other alternatives with their high energy storage capacity, high energy density (kWh/kg), long service life, high charge-discharge rate and gradually decreasing cost. The ionic conductivity of the liquid electrolytes and solid electrolyte interphase (SEI) layer formed on the electrode's surface are some of the most important factors controlling the performance of the lithium ion batteries. Electrolyte additives provide contributions such as increasing the ionic conductivity of the electrolyte and forming the SEI layer without significantly increasing the production cost and changing the production process. In this work, triphenylphosphine boron trifluoride (BF3.PPh3) was synthesized in accordance with the literature to be used as an electrolyte additive in Li/LiCoO2 half-cells. FTIR, XPS, XRD and NMR analysis techniques were used to determine the structure and composition of the synthesized substance. The battery performance was investigated by adding certain amounts of BF3.PPh3 in 1 M LiPF6- EC/DMC/DEC (1:1:1 by volume) electrolyte. CR2032 coin cells were assembled with the electrodes and electrolytes prepared in the laboratory. The electrochemical behaviors of the battery were investigated via cyclic voltammetry and charge-discharge test. The addition of 0,5% wt and 1% wt BF3.PPh3 into the electrolyte improved the ionic conductivity and the capacity retention of the lithium ion battery. The results show that BF3.PPh3 has potential applications in lithium ion batteries.