In the present study, a nanociystalline GeO2/C core shell was synthesized by a cost-effective and simple citric-gel method for various parameters, and the effects of these parameters on the microstructural and electrochemical properties of the GeO2/C core shell were investigated. Thermo-gravimetric-analysis showed that the combustion of gel-complexes occurred in the temperature range from 178 to 247 degrees C. Among the samples pre-heated at 150 degrees C, the sample pre-heated for 4h had the highest surface area (11.12 m(2) g(-1); particle size similar to 30 nm). TEM analysis revealed that the citric-gel synthesized GeO2 was encapsulated with carbon. This carbon encapsulation acted as a critical buffer layer against capacity degradation in the fabricated electrodes. The optimized sample showed a specific capacity of 738 mA h g(-1) and maintained its reversibility after 50 cycles at a capacity of 697 mA h g(-1). The electrode containing the optimized sample showed a reversible capacity of 530 mA h g(-1) at 1 C rate (C) 2013 Elsevier Ltd. All rights reserved.