Urchin-like 3D NiFe₂O₄ with 1D radially oriented nanorods as anode for lithium-ion based dual-ion pseudocapacitor

Lithium dual-ion pseudo-capacitors (L-DICs) are attracting more and more attentions as electrochemical energy storage facilities, owing to high working plateaus, low cost, and environment friendly. In this work, three-dimensional (3D) urchin-like NiFe₂O₄ with one-dimensional (1D) radially oriented nanorods is synthesized via hydrothermal method, which is used as anode material in L-DICs. The coordinated buffer space of the 3D microsphere and large length-to-diameter ratio of the 1D nanorods guarantee the capacitive-controlled Li storage and ensure the cycle stability of the electrode. By applying graphite as cathode, the L-DICs based on the urchin-like NiFe₂O₄ as anode deliver a high reversible discharge capacity of ∼66 mAh g⁻¹ at 1 A g⁻¹ for over 350 cycles with 82.5% capacity retention.