Production of cathode material for lithium-ion batteries by using different processes and materials

In this thesis, we developed layered cathode materials using morphology modification, alternative raw material addition and surface coating techniques. Then, we investigated the relationship between structural properties and electrochemical performances. In this regard: (i) A micro-fluidization technique was used to apply a high shear force to decrease particle thickness and increase the distance between the layers that positively alter the electrochemical properties. We observed that the micro-fluidization process increased the cyclic stability of layered cathodes. Particularly, LiCoO2 which micro-fluidized with low cycle exhibits remarkable improvement in capacity retention compared to unprocessed LiCoO2. (ii) The potential use of MHP as an alternative Ni, Mn and Co source and a multielement doping agent thanks to its useful content in NMC synthesis has been discussed. NMC111 and NMC622 were synthesized with solid-state, Pechini and sol-gel techniques by adding MHP in different ratios. We observed that up to 10 %, 2 % and 3 % MHP could be added into solid-state synthesized NMC622, Pechini synthesized NMC622 and sol-gel synthesized NMC111, respectively, by preserving the layered oxide crystal structure and electrochemical performance. (iii) The surface of NMC particles coated by LLZO ionic conductor to create a barrier between the liquid electrolyte and the cathode surface to improve cyclic stability and rate capability. Using the sol-gel technique, we coated the surface of NMC532 powders with nano cubic-LLZO lithium-ion conductors in different ratios. We also optimized the calcination temperature after the coating process. The results showed that 2 % LLZO coated NMC sample indicated improved cyclic stability and rate capability. The characterization of synthesized materials was carried out by XRD, Rietveld, SEM, TEM and Raman techniques. The electrochemical performances of cathodes were examined by galvanostatic charge-discharge tests, CV and EIS analyses.