过渡金属磷化物(TMPs)因其高理论容量而成为极具潜力的锂离子电池负极材料. 然而, 严重的体积膨胀和缓慢的反应动力学阻碍了其实际应用. 本工作报道了一种源自普鲁士蓝类似物(PBAs)并经多巴胺辅助包覆策略制备的界面工程化双金属Fe-Ni-P异质结构, 该结构被封装于多级碳基质中. 所得Fe-Ni-P@C复合材料呈现出分级核壳架构: 导电碳壳有效缓冲体积变化并增强结构稳定性, 而精心构筑的Fe-Ni-P异质界面则加速了电荷转移与反应动力学. 这种协同设计提供了丰富的电化学活性位点及稳健的离子/电子传输通道, 使其在2 A•g⁻¹电流密度下循环1000次后仍保持291.4 mAh•g⁻¹的高可逆比容量. 将其与LiFePO₄正极组装成全电池, Fe-Ni-P@C负极循环100次后容量保持在113.2 mAh•g⁻¹, 展现出良好的实际应用前景. 本研究突显了界面工程和分级碳限域在稳定双金属磷化物负极方面的有效性, 为开发用于先进锂离子电池及相关储能系统的高性能电极材料提供了一种富有前景的设计策略.

Transition metal phosphides (TMPs) are considered promising anode materials for lithium-ion batteries because of their high theoretical capacities and suitable operating potentials. Nevertheless, their practical application is still severely restricted by large volume fluctuation, particle pulverization, and sluggish charge-transfer/ion-diffusion kinetics during repeated lithiation and delithiation. In this work, a hierarchical carbon-confined bimetallic Fe-Ni-P heterostructure (Fe-Ni-P@C) was rationally constructed by using a Prussian blue analogue (Fe-Ni-PBA) as the precursor, followed by a dopamine-assisted coating strategy, carbonization, and phosphorization. Density functional theory calculations indicate that the introduction of Ni into the phosphide system increases the electronic states near the Fermi level, which is favorable for electronic transport. Structural characterization demonstrates that the obtained Fe-Ni-P@C composite preserves a uniform cubic morphology with an average particle size of about 120 nm, possesses a conductive carbon shell with a thickness of about 15 nm, and contains abundant internal voids and FeP/NiP₂ heterointerfaces. In addition, the material exhibits a high specific surface area of 798.24 m²•g⁻¹ with rich mesoporous features, which can effectively facilitate electrolyte penetration and provide sufficient electroactive sites. Benefiting from the synergistic effects of hierarchical porous architecture, conductive carbon confinement, and heterointerface engineering, the Fe-Ni-P@C electrode delivers a high specific capacity of 1025.4 mAh•g⁻¹ at 0.1 A•g⁻¹ and maintains 291.4 mAh•g⁻¹ after 1000 cycles at 2 A•g⁻¹. Electrochemical kinetic analyses further reveal that Fe-Ni-P@C possesses the lowest charge-transfer resistance, a Li⁺ diffusion coefficient of 5.58×10⁻¹⁰ cm²•s⁻¹, and a high pseudocapacitive contribution of 77.99% at 1.0 mV•s⁻¹, confirming its fast reaction kinetics and efficient charge-storage behavior. Furthermore, the assembled LiFePO₄//Fe-Ni-P@C full cell retains a discharge capacity of 113.2 mAh•g⁻¹ after 100 cycles and can successfully power a small blue LED. This study demonstrates that combining PBA-derived heterostructure design with dopamine-derived carbon confinement is an effective strategy for developing high-performance TMP-based anodes for advanced lithium-ion storage.