Surfactant and ethanol-assisted hydrothermal synthesis of Co-free Ni0.9Mn0.05Al0.05(OH)2 cathode material precursor and the influence of Zr doping on battery cathode material performance

Abstract

A considerable amount of research is dedicated to improving electrochemical energy storage, primarily focusing on Li+ ion systems, which are widely used in portable devices and transportation. The demands for higher capacities and energy densities in electrode materials are increasing for electronic devices and vehicles. Nanotechnology is an emerging field that offers potential for the advancement of efficient and improved batteries, especially Li+ ion batteries (LIBs). The significance of cathode materials in LIBs is paramount, as these batteries are still limited by their cathode design. Here, we explore the possibility of synthesizing cathode active materials (CAMs) that fulfil battery specification requirements through various synthesis techniques. The conventional method of co-precipitation can achieve this, but the hydrothermal method discussed in this manuscript provides enhanced control over the morphology and structure of the synthesized precursors. The focus of the thesis is on introducing a novel category of cobalt-free (Co-free) cathode material, which contains 90 mol % of Ni, along with Al and Mn. This is achieved through a surfactant-assisted hydrothermal approach. The cathode active material, composed of Zr-dopped flower-like microspheres made up of multiple thin petals, was successfully prepared. This study examines the various factors that affect grain growth and explores the modifications associated with hydrothermal reaction temperature and the use of suitable alkaline media. Additionally, the study investigates the impact of Zr as a dopant, which shows comparable performance. The precursors and lithiated metal oxides are characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and galvanostatic charge-discharge measurements, which is employed to evaluate the cell performance of the all as-synthesized LiNi0.9Mn0.05Al0.05O2. The results indicate that the non-doped LNMAO2 demonstrates the highest initial capacity (49.8 mAh.g−1) and capacity retention among the prepared cells.