The electrochemical performance of a hybrid asymmetric supercapacitor with activated carbon (AC) as anode and a lithium-ion intercalated compound LiNi0.5Mn1.5O4 as cathode was studied. By using metal acetate precursors as starting materials in solid state reaction method, pure LiNi0.5Mn1.5O4 was formed at low temperature. The role of precursors on the formation of material at low temperature and short period of time is presented. XRD confirms the cubic spinel structure (space group, Fd3m) and SEM shows the particles of size around 1 mu m. The effect of the modified solid state reaction route on the structural and electrochemical properties was investigated. The fabricated hybrid supercapacitor, AC/LiNi0.5Mn1.5O4 in a non-aqueous electrolyte 1.0 M LiPF6/EC-DMC exhibits a sloping voltage profile from 1.0 to 3.0 V and delivers a specific energy of ca. 56 Wh kg(-1). Moreover, it exhibits excellent cycling performance with less than 5% capacity loss over 1000 cycles. (C) 2009 Elsevier B.V. All rights reserved.