Stabilization of ZnMn2O4 Nanoparticle Electrodes by Electrolyte Modulations and Improved Li-Ion Storage

The low capacity of the graphite anode has initiated a lot of interest in low cost, earth-abundant, high-capacity transition metal oxides like ZnMn2O4 (ZMO) for Li-ion battery applications. This study leads to a facile precipitation method followed by structural, morphological, and electrochemical investigations on ZMO. Different electrolyte formulations involving the combination of different salts and solvents were investigated to gain a comprehensive understanding. The attempt led to an inference that LiTFSI salt in EC:DMC mixed solvents outperformed other electrolyte formulations investigated in this work. Performance metrics of 73% capacity retention occurred when the specific current increased from 100 to 1000 mA/g, with a reversible capacity of 874 mAh/g at 100 mA/g and 638 mAh/g at 1000 mA/g. At the end of electrochemical testing, ex situ surface chemical and morphological analyses were carried out to correlate the performance with different electrolyte formulations. It is realized that the SEI layer formed on the ZMO nanoparticle surface with the LiTFSI-EC:DMC electrolyte is stable and uniform and created a conformal layer that maintained the integrity of the nanoparticles during lithiation/delithiation reactions. Hence, the electrochemical rate performance and cycling of this electrolyte outperformed all other formulations investigated.