Fabrication of Eco-friendly Lithium Titanium Phosphate/Lithium Polysulfide/Graphite Rechargeable Batteries

Abstract

The average global temperature has not changed by more than 1° C over 10,000 years. It is predicted
that the global temperature will rise by 3° C by the year 2100, unless action is taken to limit
temperature increment to 1.5° C. Since the beginning of the century, the field of lithium-ion battery
development has skyrocketed. Li-ion batteries have become the primary electrical energy storage
device for portable electronic devices in today's world. This study aims to innovate high-performance,
less toxic, low-cost rechargeable lithium-ion batteries with lithium titanium phosphate as anode
material, graphite as cathode material and lithium polysulfide as electrolyte under standard laboratory
conditions. Cell performance was analyzed by observing the charge and discharge curves. In this
research work, the charge-discharge performance was analyzed using LabJack U3-HV with LabJack
software. The cell voltage was recorded with time, and using a fixed resistor, current flow was
calculated. The cell showed initial voltage of 1.3 V and 10 mA in the first charge curve, the initial
voltage was increased to 3.2 V in the second charge curve, and the current has decreased to 5.1 mA.
During the discharging process, fast discharging was observed from 2.2 V to 0.2 V, giving current
from 3.1 mA to 0.3 mA across 657 Ω. In the charging curve, small voltage plateaus can be seen
around 1.5-2.0 V. It was observed that the voltage of charging cycles increases due to the
increasement of the cell's internal resistance with time. When increasing the charging voltage across
the cell, the current passing through the circuit was decreased by proving Ohm’s law and discharge
curves demonstrated fast discharge within 60 minutes.

Keywords: Li-ion, Lithium titanium phosphate, Charge curve, Discharge curve