A high throughput experimental and computational approach for high voltage Mn based spinel materials exploration

Abstract

Lithium-ion batteries (LIBs) currently stand as the most performant rechargeable batteries in the market although increasing their energy density, durability, sustainability, and safety is still needed. To accelerate materials discovery, high-throughput (HT) computational and experimental techniques are required, as the conventional manual approach is time-consuming and costly.In this thesis, an autonomous platform has been successfully developed for the synthesis of inorganic materials with HT capabilities. It integrates an in-house built module that enables the mix of reagents minimizing manual handling. This platform allows to synthesize, following different synthetic approaches (i.e. sol-gel, pechini and solid-state), 200-500mg of 12 samples simultaneously, ensuring that all characterizations are done on a single batch to ensure representativeness. The efficiency of this platform is showcased by performing sol-gel synthesis of two systems: (i) LiFe0.5Mn1.5O4 (LFMO), to evaluate different synthetic parameters, and (ii) the Li-Mn-Ni oxide system to explore a part of the phase diagram.The high voltage LFMO spinel has been further studied in detail. This system was selected due to its environmental friendliness and low cost, as well as, for exhibiting a theoretical capacity of 148mAhg-1 and operating at high voltage (c.a. 4,4 Vvs. Li/Li+ in average). To understand its electrochemical behavior, a computational analysis considering different Fe/Mn distributions has been performed. Structural parameters and electrochemical behavior including phase stability, voltage evolution and redox processes upon (de)lithiation has been evaluated. Afterwards, a HT experimental screening of synthetic parameters has been done focusing on the impact of synthetic parameters and antisite defects on LFMO's structural and electrochemical properties, showcasing the importance of controlled synthesis in minimizing antisite defects to optimize its energy storage efficiency. By the combination of theoretical and HT experimental approaches this thesis sheds light to comprehensively understand LFMO behavior as a promising material for LIBs.