In the pursuit of detecting the first endohedral polyhedral borane complex, we report a quantum-chemical computational study of energy landscapes for diexo isomers derived from Li2B12H12 and the exo/endo isomer Li@{LiB12H12}. Geometries, electronic structure and energy barriers are computed for the interconversion between diexo isomers and the exo/endo isomer, the latter leading to a thermal injection/ejection mechanism of Li+ from outside/inside the complex [LiB12H12]. (c) 2010 Elsevier B.V. All rights reserved.