In the present study, a novel hybrid ammonia fuel cell and battery system is conceptually developed and studied electrochemically and thermodynamically. The novel system proposes a new method to enhance the utilization of electrochemical energy. The fuel cell cathode comprises of a regenerative nickel electrode. Ammonia is utilized as fuel at the fuel cell anode. During fuel cell operation, the half-cell electrochemical reaction at the cathode regenerates the electrode. This electrode acts as the anode during battery discharge. In addition, ammonia is formed at the battery cathode electrode, which is reused as fuel at the fuel cell anode. A performance assessment of the proposed system is conducted. The reversible potentials of the fuel cell and battery systems are evaluated as 0.54 V and 0.73 V respectively. The average energy and exergy efficiencies of the fuel cell system are obtained as 54.2% and 50.9% respectively. In addition, the efficiency of the battery system is found to be 75%. To analyse the system performance with changing operating conditions and parameters, several parametric studies are conducted.