Glucose-derived carbon confinement stabilizes flake-Like ZnSe for high-rate sodium storage

Sodium-ion batteries require anode materials that can sustain rapid Na + transport while tolerating significant volume changes. Here, flake-like ZnSe/C is prepared by freeze-drying a Zn-citrate-derived lamellar precursor with selenium and glucose, followed by one-step selenization. During heating, glucose carbonizes in situ and confines ZnSe nucleation, producing fine ZnSe domains distributed within a disordered carbon-sheet matrix. As a sodium-ion battery anode, ZnSe/C delivers 224.4 mAh g -1 at a high current density of 5.0 A g -1 and retains 192.8 mAh g⁻¹ after 1000 cycles, compared with 43.3 mAh g -1 for directly selenized ZnSe. Electrochemical measurements suggest lower charge-transfer resistance and faster apparent Na+ transport. First-principles calculations using a graphene-like carbon/ZnSe contact show carbon-derived states near the Fermi level and a decrease in the Na migration barrier from 0.513 to 0.447 eV. The results show that carbon confinement improves high-rate durability by limiting ZnSe coalescence and maintaining electronic contact.