Nanoconfinement of metal borohydrides is a promising route for improvement of their kinetic and thermodynamic properties related to hydrogen storage. Since the atomic-scale properties of nanoconfined LiBH4 remain under debate we propose a model of such a structure. Within extensive density functional theory calculations we consider continuous transformation of the lithium borohydride equilibrium structures from 3-dimensional to 1-dimensional, Such structures consist of single linear chains, linear ribbons and 3-dimensional chains, and together with the low temperature bulk phase they reproduce B-11 NMR spectra observed in LiBH4 confined in porous carbon. The present model suggest that nanoconfined LiBH4 consists of a dense bulk-like region and loosely distributed chains and ribbons of Li-BH4. Even with the low effective density of loosely distributed LiBH4 they occupy region with thickness as small as a quarter of a pore diameter. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.