Co-MOF-derived stalk-flower like NiCo-LDH homostructure towards boosting electrochemical energy storage

The rational design of the heterostructure of multi-component materials acts on electrochemical properties . However, the effect of structure and component alone on the performance is ignored. Homostructure can reflect the advantages of structural design more directly and fully tap the potential of the material itself. Herein, the homogeneous stereostructure with NiCo-LDH nanostalks (NiCo-LDH S ) and NiCo-LDH nanoflowers (NiCo-LDH F ) was synthesized through simultaneous Co-MOF in-situ etch and electrodeposition . NiCo-LDH S not only preserves the shape of MOF rods, but also forms a firm adhesion to nickel foam. The coated NiCo-LDH F on NiCo-LDH S increases the loading of pseudocapacity material. As a result of the high capacity of Ni(OH) 2 , the high conductivity of Co(OH) 2 , as well as the stalk-flower stereostructure, the NiCo-LDH S-F electrode demonstrates a specific capacity of 2058 F ​g −1 (13994 ​mF ​cm −2 ) at 1 ​A ​g −1 , along with an ultrahigh rate capability, retaining 73.9 ​% of its capacity at 20 ​A ​g −1 . Moreover, the assembled NiCo-LDH S-F //AC hybrid supercapacitor (HSC) exhibits striking energy and power densities of 48.44 ​Wh·kg −1 (0.78 ​mWh·cm −2 ) and 800 ​W ​kg −1 (12.8 ​mW ​cm −2 ), respectively. Notably, after 10,000 consecutive charging and discharging cycles, the device maintains a capacity retention of 85.36 ​%, demonstrating its good cycling stability. These findings prove the essentiality of designing homogeneous structure for the advancement of energy storage performance. Herein, a Co-MOF-derived NiCo-LDH S-F with a stalk-flower stereo architecture was prepared as the cathode of hybrid supercapacitors. Unlike the traditional etching method using a Ni 2+ solution, a mixed electrolyte of Co 2+ and Ni 2+ ions is selected to in-situ etch of MOF and electrodeposition of NiCo-LDH F nanoflowers simultaneously. MOF-derived NiCo-LDH S not only preserves the shape of MOF to generate the stalk-like LDH, but also forms a firm adhesion to nickel foam. Coupled with the electrodeposited NiCo-LDH F nanoflowers, the stalk-flower NiCo-LDH S-F is designed to omni-directionally support the layered structure, which endows NiCo-LDH S-F with high loading and excellent performance. This special combination of stalks and flowers may hold immense potential for driving innovation in the design and utilization of LDHs and other redox-type materials, thereby advancing the field of aqueous energy storage. • Homogeneous stereostructure of stalk-flower like NiCo-LDH is firstly constructed. • Co-MOF-derived NiCo-LDH stalks contribute to high attachment to nickel foam and high mass loading. • Hybrid supercapacitor illustrates an energy density of 0.78 ​mWh·cm −2 .