The forced periodic reversal of the flow is proposed for the case of a Solid Oxide Fuel Cell (SOFC) monolith. A one-dimensional non-steady state heterogeneous model is applied to an investigation of H-2 electrochemical oxidation in a co-current flow solid oxide monolithic fuel cell. Results are reported on the transient evolution along the reactor, of the species conversion, temperature distribution, thermodynamic energy conversion efficiency and volumetric power density. This novel transient operation of an SOFC leads to improved and highly efficient performances, thus allowing for a combination of the concepts of a regenerative heat preheater and of an electrocatalytic converter, in a single SOFC monolithic assembly.