Electrochemical studies on Na2FeP2O7 pyrophosphate enhanced with SWCNT as intercalation compounds for Na-ion batteries: An insight into sensitive mode operations

A sol-gel assisted method followed by post calcination is utilized here to synthesize polyanionic type Na2FeP2O7 (NVP) material as a cathode for Na-ion batteries. The NVP with super carbon black (SCB) as a conducting agent delivers a specific discharge capacity of 68 mAh g (1) at 0.1C in the initial cycle. To improve the specific capacity, stability and reversibility the different carbon sources such as Single Walled Carbon Nanotube (SWCNT) and Multiwalled Carbon Nanotube (MWCNT) are physically mixed with the as-synthesized NVP material. The SWCNT mixed material shows a better specific discharge capacity of 73 mAh g (1) at the initial cycle at 0.1C rate. The structure modification with the SWCNT addition fastens the reaction kinetics, diffusion and the movement of the Na-ions, which leads to better capacity and rate performance. (c) 2020 Elsevier B.V. All rights reserved.