Heterojunction-Engineered Co, Fe co-doped Ni2P@Ti₃C₂Tₓ with 3D Network Structure for Enhanced Lithium Storage

In this work, a unique three-dimensional (3D) network NiFeCoP@Ti₃C₂Tₓ composite, consisting of Co, Fe co-doped Ni 2 P (NiFeCoP) nanosheets anchored on Ti₃C₂Tₓ nanosheets via heterojunction, was situ constructed by phosphidizing the NiFeCo-LDH@Ti₃C₂Tₓ precursor. The 3D network structure establishes a 3D conductive network while generating a built-in electric field at the heterointerface, which efficiently accelerates electron/ion transport and simultaneously improves the structure stability of the electrode. DFT calculations demonstrate that Co doping further optimizes the electronic structure of NiFeCoP, introduces additional active sites, thereby promoting electrochemical reaction kinetics. Meanwhile, the synergistic effect among Ni, Fe, and Co with different redox potentials effectively buffers the volume changes during charge/discharge processes. Consequently, NiFeCoP@Ti₃C₂Tₓ as lithium ion batteries (LIBs) anode shows outstanding electrochemical performance at different current density (950   mAh/g after 340 cycles at 0.5   A/g, 816   mAh/g after 900 cycles at 1   A/g, 541   mAh/g after 1000 cycles at 2   A/g).