Destabilization of LiBH4 by nanoconfinement in poly (methyl methacrylate)-co-butyl methacrylate (PMMA-co-BM), denoted as nano LiBH4-PMMA-co-BM, is proposed for reversible hydrogen storage. The onset dehydrogenation temperature of nano LiBH4-PMMA-co-BM is reduced to similar to 80 degrees C (Delta T=340and 170 degrees C as compared with milled LiBH4 and nanoconfined LiBH4 in carbon aerogel, respectively). At 120 degrees C under vacuum, nano LiBH4-PMMA-co-BM releases 8.8 wt.% H-2 with respect to LiBH4 content within 4 h during the 1st dehydrogenation, while milled LiBH4 performs no dehydrogenation at the same temperature and pressure condition. Moreover, nano LiBH4-PMMA-co-BM can be rehydrogenated at the mildest condition (140 degrees C under 50 bar H-2 for 12 h) among other modified LiBH4 reported in the previous literature. Due to the hydrophobicity of PMMA-co-BM host, deterioration of LiBH4 by oxygen and humidity in ambient condition is avoided after nanoconfinement. Although the interaction between LiBH4 and the pendant group of PMMA-co-BM leads to a reduced hydrogen storage capacity, significant destabilization of LiBH4 is accomplished. Copyright (c) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.