We present results of Raman and infrared absorption spectroscopy research on phonons in LiMnPO4-a new material for high capacitance rechargeable lithium-ion batteries. There is a significant interest in the structural and electrical properties of this material, because the battery performance depends strongly on the rate of lithium diffusion. Nanopowder of LiMnPO4 was obtained via a modified sol-gel method from salts of lithium and manganese. This method is cheap and effective so it is promising for the most popular applications. The material showed sharp phonon peaks in Raman and infrared spectra. In the Raman spectra, the strongest peak was A(g)nu(1) mode at energy 117.77 meV (950.1 cm(-1)), at 4K. At room temperature, its energy decreased (due to phonon-phonon interaction) to 117.5 meV (947.5 cm(-1)). The Gruneisen parameter found for this oscillation mode was relatively low, gamma(Ag nu 1) = 0.5, at about 300 K. Since the mode consisted mainly of the symmetric PO4 tetrahedra oscillations, the low gamma(Ag nu 1) value indicated that the temperature influenced rather Li-O and Mn-O bonds than the P-O bonds forming the LiMnPO4 structure. The thermal dependencies of the antisymmetric modes (A(g)nu(3) and A(g)nu(4)) were stronger (gamma(Ag nu 3) = 0.7, gamma(Ag nu 4) = 1.4) what suggested that these modes experienced stronger coupling. The thermal broadening of the A(g)nu(1) mode could be described in wide temperature range by exponential dependence with activation energy of 65 meV (about two times smaller than the A(g)nu(1) energy), what suggested a symmetric two-phonon decay. (C) 2011 Elsevier B.V. All rights reserved.