Electrochemical performance of single crystal belt-like NH4V3O8 as cathode material for lithium-ion batteries

Abstract NH 4 V 3 O 8 with belt-like morphology has been synthesized via a hydrothermal process, using acetic acid as acidulant. The resulting phase-pure NH 4 V 3 O 8 microcrystals have smooth surfaces and are typically 25–45 μm long, 2–15 μm wide, and 0.6–1.2 μm thick. Electrochemical studies by means of cyclic voltammetry and galvanostatic cycling show that the pristine material is a suitable host for reversible Li + de-/intercalation. Analysis of the peak currents from cyclic voltammetry by means of the Randles-Sevcik equation suggests that the Li + de-/intercalation is diffusion-controlled with D  ∼ 5·10 −15  cm 2  s −1 . The maximum discharge capacity, at 20 mA g −1 , amounts to 299 mA h g −1 . At 90 mA g −1 , it is still 201 mA hg −1 with a capacity retention of 90% in the 100th cycle, indicating the belt-like NH 4 V 3 O 8 being a promising candidate for application as cathode material in secondary lithium-ion batteries.