Influence of electrode fabrication process on nanocrystalline tin oxide electrochemical behaviour for high voltage SnO2/LNMO full cell Li-ion battery

Tin oxide is one of the most promising anode materials to replace graphite in the next generation lithium-ion batteries thanks to its high theoretical specific capacity, low cost and large availability. Unfortunately, its large-scale application is still limited, due to marked capacity loss and poor cyclability. Recent findings demonstrated improved reversibility of the electrochemical reactions through the optimization of SnO2 particles size. In this frame, the sol-gel method has proved to be one of the most interesting synthesis processes to obtain mono and polycrystalline SnO2 particles, which guarantee higher reversibility of the conversion reaction. In this work, SnO2 nanoparticles was synthesized by sol-gel method, with an average size of 5-50 nm, depending on the post calcination temperature. Subsequently, the optimization of the electrode composition in terms of mass loading and binder allowed to achieve a specific capacity of 350 mAh g-1, with a Coulombic efficiency of 99.9 % after 100 cycles at high current rate of 0.75 A g-1. Finally, the optimized and pre-lithiated SnO2 anode was coupled with the high voltage LiNi0.5Mn1.5O4 (LNMO) cathode in full-cell configuration, and the contribution of the voltage window and formation step to the final cell capacity was studied to determine the optimum conditions at which high cycling stability can be obtained.