We report all-solid-state lithium ion batteries based on nano-sized Li2FeSiO4 coated by carbon cathode materials with fast rechargeable (67.5 mA h g1 at 30 C) and high capacity (258.2 mA hg1 with 1.55 Li-ion storage at 1 C within 1.5–4.5 V) performances for the first time. By investigating and comparing with Li2FeSiO4, LiFePO4 and LiNi0.5Co0.2Mn0.3O2 cathode materials for all-solid-state lithium ion batteries, the mechanism of the higher rate performance of the Li2FeSiO4 based battery is found to be attributed to the high temperature depended diffusivity and electrical conductivity, which are increased by nearly four orders of magnitude from 300 K to 373 K, and also to permeation of the cathode/electrolyte solid-solid interface to generate the overlapping between Li2FeSiO4 particles and electrolyte.