The role of liquid Sn in a direct carbon fuel cell with a Ni–yttria-stabilized zirconia (YSZ) cermet anode is investigated in terms of enhancing the solid fuel-to-solid anode interface and intrinsic electrocatalytic activity. Sn-mixed carbon black particles undergo a transformation from solid to liquid phase as the cell temperature rises, thereby leading to the formation of more favorable interface between carbon fuels, liquid Sn, and Ni–YSZ anodes. Moreover, additional Ni-impregnated Sn–carbon fuels show that further improvements in cell performance can be achieved by increasing the oxidation of carbon to CO. As a result, we observe a maximum power density of 60.5 and 105mWcm−2 at 900°C by using Sn–carbon and Ni–Sn–carbon fuels, respectively.