Effect of composition of LiMn₂O₄ cathode sheet on the electrochemical performance of lithium ion battery

The effect of composition of LiMn₂O₄ sheet on the electrochemical performance of lithium ion battery has been studied. LiMn₂O₄ powder is synthesized by solid state reaction method using raw material such as LiOH.H₂O and MnO₂. Raw materials are stoichiometrically mixed and milled using planetary ball milling for 4 hours to become precursor. The precursor is sintered using a muffle furnace at 800 °C for 4 hours in a free air atmosphere. The sintered material is pulverized and sieved 200 mesh to form a fine LiMn₂O₄ powder. The material is analyzed by XRD to determine the phase and crystal structure. Powder is prepared for sheet by mixing with PVDF binder and carbon black additive in various ratio such as 85:10:5, 88:8:4 and 90:7:3. After becoming slurry, the slurry was coated onto Al foil with 300 µm in thickness and dried at 70 °C for an hour. The sheet is assembled into a half cell battery with Li metal as the counter electrode and LiPF₆ as liquid electrolyte. The battery cell is measured by using the automatic battery cycler WBCS 3000 to determine the electrochemical performance. The measurement showed that samples with composition 90% active material has highest capacity with 3.6 mAh but gives bad cycle. (paper)