Morphology Evolution of NiFe Layered Double‐Hydroxide Nanoflower Clusters from Nanosheets: Controllable Structure–Performance Relation for Green Energy Storage

NiFe‐layered double hydroxide (NiFe‐LDH) as electrode materials for supercapacitors are successfully prepared by green and one‐step hydrothermal method without template. The controllable structure–performance relation of NiFe‐LDH nanoflower clusters (NCs) for green energy storage is realized by regulating reaction time. The morphology evolution of NiFe‐LDH is elucidated. NiFe‐LDH‐24 h offers a unique NC structure and has specific capacitance of 635.8 F g −1 at 1 A g −1 , which is larger than one of the reported pure NiFe‐LDHs so far. The improved electrochemical performance of NiFe‐LDH‐24 h NCs is due to its unique structure and synergistic effect between components that cause the larger specific surface area and more electroactive sites for Faradic reaction. The reaction kinetics reveals the electrochemical energy storage mechanism of the NiFe‐LDH‐24 h NCs. The energy storage is contributed by diffusion and surface capacitance. The electrochemical performance of NiFe‐LDH‐24 h NCs is further modified for the first time by doping F, and the specific capacitance of F‐doped NiFe‐LDH‐24 h NCs (1942 F g −1 ) is increased by 3 times higher than that of NiFe‐LDH‐24 h NCs. This work provides a more solid theoretical basis for green energy storage through morphology control and doping modification strategies.