High Performance of Na_(2/3)Ni_(1/4)Mn_(3/4)O_2 Thin-Film Cathode for Sodium-Ion Micro-Batteries

摘要

Thin films of Na_(2/3)Ni_(1/4)Mn_(3/4)O_2 were prepared on stainless steel substrates by pulsed laser deposition technique. X-ray diffraction and Field-emission Scanning Electron Microscope results show that the thin film deposited at 750°C is highly preferred orientation with homogeneous nanoscale particles. Galvanostatic charge/discharge measurement results reveal that the reversible capacity retention is 91% after 30 cycles with a high initial discharge capacity of 175.3 mAhg~(-1) at a current density of 13 mAg~(-1). It also exhibits excellent rate capability, as the current density increases to 260 mAg~(-1), about 80% of its initial capacity can be retained. After the high rate measurement, the NNMO electrode can deliver a discharge capacity of 110.4 mAhg~(-1) when the current density was reduced back to 13 mAg~(-1).