Li0.95Na0.05MnPO4/C Nanoparticles Compounded with Reduced Graphene Oxide Sheets for Superior Lithium Ion Battery Cathode Performance

Sodium-substituted LiMnPO4/C/reduced graphene oxide (LNMP@rGO) was synthesized in this study via freeze drying and carbon thermal reduction method with graphene oxide as carbon source. Sodium ion doping is optimized and rGO effects are evaluated by XRD, SEM, TEM, BET, Raman, and electrochemical performance measurements. Well-distributed nanoparticles with average size of ~50 nm are evenly distributed on the surface or intercalation between rGO layers, resulting in a porous ion/electronic conductive network. Compared to 122.3 mA h g−1 in unmodified LNMP, the best LNMP@rGO (20 mg rGO) exhibits an excellent initial discharge capacity of 150.4 mA h g−1 at 0.05 C at 122.9% of the initial capacity. The capacity retention rate is 95.8% of the initial capacity after 100 cycles at 1 C. Capacity of 101.2 mA h g−1 is preserved even at rates as high as 10 C.