A lithium accumulator includes at least two three-dimensional electrodes separated by a separator and encased together into an accumulator body with an electrolyte that is a non-aqueous solution of a lithium salt in an organic polar solvent. The two electrodes have a minimum thickness of 0.5 mm each. At least one electrode is a homogenous, compressed mixture of an electron conductive component and an active material. The active material is capable of absorbing and extracting lithium in the presence of electrolyte. The porosity of the pressed electrodes is 25 to 90%. The active material has morphology of hollow spheres with a wall thickness of maximum 10 micrometers, or morphology of aggregates or agglomerates of maximum 30 micrometers in size. The separator includes a highly porous electrically insulating ceramic material with open pores and porosity from 30 to 95%.