The performance of a full-duplex cooperative cognitive network is investigated under Nakagami-m fading. The secondary source and the relays are energy-constrained nodes and harvest energy from the primary network to transmit their information. The direct link between source and destination in the secondary network is considered as useful information at destination where joint-decoding is applied upon the signals received from source and relay. We derive an approximated closed-form expression for the outage probability of the proposed scheme. Results show that the proposed scheme outperforms the half-duplex and direct transmission schemes in the particular scenarios under consideration. Moreover, the performance in terms of outage probability of the proposed scheme is further improved through the use of multiple relays.