Amorphous/Crystalline@Amorphous Core–Shell Electrode Materials With Crystalline Electron‐Transport Networks for Energy Storage and Conversion

ABSTRACT Amorphous phases usually possess dense active sites and abundant dangling bonds, while crystalline counterparts provide better electronic conductivity and structural stability. Herein an amorphous/crystalline@amorphous core–shell heterostructure (a/c‐CoNiP 300 @a‐NiFe LDH/NF) is synthesized to combine the amorphous high active‐site density and crystalline superior conductivity & stability. The crystallinity of the core is optimized by regulating the phosphorization temperature, as deviations from the optimal range degrade electrochemical performance. The constructed heterostructure effectively facilitates electron transfer and local charge redistribution. Its unique small‐sized morphology, combined with superhydrophilic and gas‐repellent surface properties, synergistically enhances electrode behavior. The material demonstrates outstanding multifunctional performance. In supercapacitors, it delivers an ultrahigh specific capacitance of 3071.64 F g −1 at 5 mA cm −2 , with an assembled hybrid device achieving 56.41 Wh kg −1 energy density. DFT calculations demonstrate enhanced interfacial charge transfer from NiFe LDH to CoNiP, improved Fermi‐level density of states, and boosted OH − adsorption across the heterointerface. Furthermore, a/c‐CoNiP 300 @a‐NiFe LDH/NF requires low potentials of only 1.31 V (vs. RHE) for the urea oxidation reaction and 160 mV (vs. RHE) for the hydrogen evolution reaction to reach 100 mA cm −2 . Its practical potential is validated in a flexible supercapacitor and a urea‐containing wastewater treatment system.