Research studies
on Na-ion batteries (NIBs) are receiving significant
scientific and commercial attention recently owing to the availability
of low-cost, safe, and abundant materials in comparison to the conventional
Li-ion batteries. The cathode material in a battery plays a crucial
role in determining its cell capacity and cycle life. NASICON-based
Na3V2(PO4)3, NVP, is known
to be a favorable cathode material for NIBs due to its structural
stability with high Na-ion mobility. The present work shows the structural
and electrochemical properties of bare NVP/C and NVP/C partially doped
with low-cost and much abundant transition element Fe/Mn at the toxic
and expensive V site. The bare NVP/C as well as the transition-metal
ion-doped NVP/C materials are prepared by the sol–gel method.
XRD and FTIR studies confirm the formation of materials exhibiting
the rhombohedral NVP structure (R3̅c) without any trace of impurities. The presence of a carbon
layer in the investigated cathode materials is confirmed by the HRTEM
micrographs; furthermore, the oxidation states of different transition-metal
elements present are evaluated by X-ray photoelectron spectroscopy.
Electrochemical studies reveal that the moderate doping of Fe/Mn in
NVP/C results in an enhancement in discharge capacities in the doped
materials at different C rates compared to the bare NVP/C sample.
The differences in their electrochemical results are explained with
respect to their Na-ion diffusion coefficient values obtained using
the Randles–Sevcik equation. A Mn-doped NVP/C material exhibits
an enhanced discharge capacity of 107 mA h g–1 at
0.1C with 90% capacity retention even after 100 cycles at 1C current
rate. At the end, a Na-ion full cell (NVMP/C||HC) comprising a Mn-doped
NVP/C cathode with the commercial hard carbon anode delivering a discharge
capacity of 90 mA h g–1 is demonstrated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.