 A “lithium orthosilicate-related” cathode compound,  , was able to support a charging capacity of 335 mAh/g.Li2MnSiO4@C porous nanoboxes were synthesized via a wet-chemistry solid-state reaction method.The material displayed a hollow nanostructure with a crystalline porous shell composed of phase-pure Li2MnSiO4 nanocrystals.