Beneficial Effect of LiFePO4/C coating on Li0.9Mn1.6Ni0.4O4 obtained by microwave heating

There is increasing interest in 5 V vs. Li/Li+ cathodes due to their high energy density; however, unfavourable reactions occur at potentials higher than 4.8 V vs. Li/Li+. In order to avoid degradation of the active material, the L0.9MNO (Li0.9Mn1.6Ni0.4O4) with spinel type structure was coated with nanoplates of LFP/C (LiFePO4 /C) with olivine type structure and a carbon layer of similar to 2 nm, seeking to improve the stability of the L0.9NMO spinel phase and retain active sites for lithium intercalation. L0.9MNO-LFP/C composite was prepared by microwave heating at power of 10 W obtaining a thin LFP/C layer of around 20 nm on L0.9MNO particles. Homogeneous layer and a low formation of by-products in the electrolyte-cathode interphase were obtained with LFP/C amounts of 4 and 6 wt%. The highest cycling stability was achieved with LFP/C amount of 4 wt% (96.8% after 100 cycles). The high rate capability was obtained in the composite with 2 wt% of LFP/C (89% retention at 20C), the effect of which is attributed to the charge transfer kinetic improvement in L0.9MNO spinel phase that the carbon coating of LFP/C provided without affecting the lithium mobility within active material.

Automated summary

In order to improve the stability of L0.9MNO spinel phase and retain active sites for lithium intercalation, L0.9MNO was coated with LFP/C through microwave heating. The composite with 2 wt% of LFP/C showed the highest rate capability due to the charge transfer kinetic improvement in L0.9MNO spinel phase provided by the carbon coating of LFP/C.