Solid State Ionics, Vol.319, 266-270, 2018
Microwave assisted synthesis, characterization and electrochemical performance of LiVPO4F cathode material
High-voltage cathode material, lithium vanadium fluorophosphate LiVPO4F, has been for the first time synthesized by a rapid two-step method based on microwave-assisted carbothermal reduction (CTR) and characterized with the use of scanning electron microscopy (SEM), X-ray diffraction and DTA/TG thermal analysis. Its electrochemical performance has been examined by galvanostatic charge-discharge cycling. Calculated lattice parameters of the obtained LiVPO4F compound were in accordance with literature. Its thermal stability up to 550 degrees C was confirmed. Charge-discharge cycling of LiVPO4F in the voltage range between 3.0 V and 4.4 V at a current rate of 7.75 mA.g(-1) (C/20) after 5 cycles showed a charge capacity of 90 mA.h.g(-1) and a discharge capacity of 58 mA.h.g(-1). For a current rate of 15.5 mA.g(-1) (C/10) after 10 cycles charge capacity achieved the value of 60 mAh.g(-1) whereas the discharge capacity was of 52 mA.h.g(-1). The discharge plateau was at 4.18 V. The presented results suggest that LiVPO4F cathode material can be synthesized by the simplified two-step microwave-assisted reduction method. Although it needs to be further optimized, the method is simpler, faster and cheaper as compared to other preparation routes.