This study proposes a novel cooling method by combining a liquid-metal phase-change material module (LMPCM) and a flat heat pipe thermal spreader (FHP) for the application of cooling electronic devices. In this mechanism, the liquid-metal phase-change material module and the flat heat pipe function as a heat storage and thermal spreader, respectively. Thermal performance of this novel design was experimentally evaluated at both steady and transient heating conditions with different heating power inputs. Results indicate that the LMPCM + FHP modules could effectively restrain the temperature rise of electronic chips and prolong the usage time of electronic devices. Furthermore, the FHP-LMPCM module outperformed other scenarios that included the LMPCM-FHP module, copper-LMPCM module, LMPCM module, FHP module and copper sheet. Moreover, results indicate that the FHP-LMPCM module could maintain the temperature of electronic devices within an allowable temperature range even under the conditions of the PCM completely melting at transient-state heating conditions, proving this cooling method to be a very promising solution for the thermal management of high power portable electronics. (C) 2016 Elsevier Ltd. All rights reserved.