MOF-Derived Bimetallic Selenide CoNiSe 2 Nanododecahedrons Encapsulated in Porous Carbon Matrix as Advanced Anodes for Lithium-Ion Batteries.

Transition metal selenides have received considerable attention as promising candidates for lithium-ion battery (LIB) anode materials due to their high theoretical capacity and safety characteristics. However, their commercial viability is hampered by insufficient conductivity and volumetric fluctuations during cycling. To address these issues, we have utilized bimetallic metal-organic frameworks to fabricate CoNiSe 2 /C nanodecahedral composites with a high specific surface area, abundant pore structures, and a surface-coated layer of the carbon-based matrix. The optimized material, CoNiSe 2 /C-700, exhibited impressive Li + storage performance with an initial discharge specific capacity of 2125.5 mA h g -1 at 0.1 A g -1 and a Coulombic efficiency of 98% over cycles. Even after 1000 cycles at 1.0 A g -1 , a reversible discharge specific capacity of 549.9 mA h g -1 was achieved. The research highlights the synergistic effect of bimetallic selenides, well-defined nanodecahedral structures, stable carbon networks, and the formation of smaller particles during initial cycling, all of which contribute to improved electronic performance, reduced volume change, increased Li + storage active sites, and shorter Li + diffusion paths. In addition, the pseudocapacitance behavior contributes significantly to the high energy storage of Li + . These features facilitate rapid charge transfer and help maintain a stable solid-electrolyte interphase layer, which ultimately leads to an excellent electrochemical performance. This work provides a viable approach for fabricating bimetallic selenides as anode materials for high-performance LIBs through architectural engineering and compositional tailoring.