NH4V3O8 with belt-like morphology has been synthesized via a hydrothermal process, using acetic acid as acidulant. The resulting phase-pure NH4V3O8 microcrystals have smooth surfaces and are typically 25-45 mu m long, 2-15 mu m wide, and 0.6-1.2 mu m 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 similar to 5.10(-15) cm(2)s(-1). The maximum discharge capacity, at 20 mAg(-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 NH4V3O8 being a promising candidate for application as cathode material in secondary lithium-ion batteries. (C) 2015 Elsevier Ltd. All rights reserved.