Wireless Sensor Networks (WSNs) are the enabling technology for smart cities, intelligent cars and transportation systems, precision agriculture, animal tracking, and all data collection and sensing-based applications. In most \{WSN\} applications, new sensor nodes are added to the network by post-deployment to assure network connectivity, to replace dead sensor nodes or to cover more regions in the area of interest. This type of network is called Multi-Phase \{WSNs\} (MPWSNs). Similarly to classical WSNs, multi-phase \{WSNs\} require security mechanisms to ensure their deployment. However, these networks need specific solutions adapted to the multiple deployments of nodes. In this paper, we review, classify and compare the existing key management schemes proposed for this type of sensor network. We illustrate both advantages and disadvantages of each multi-phase key management scheme. Finally, we give some directions to design lightweight robust key management for MPWSNs.