RETRACTED: Nanoconfinement of multimetallic phosphides in carbon polyhedra via interfacial M-P-C bonding enabling high-energy lithium-ion capacitors

Transition metal phosphides (TMPs) are appealing anodes for lithium-ion capacitors because of their high theoretical capacities, but low conductivity and drastic volume changes remain critical barriers to practical use. Here we report a TMP heterostructure anode material featuring 10 nm CoP 2 and GeP 2 nanoclusters confined within N-P co-doped carbon polyhedra (CoP 2 -GeP 2 @NPC) via M-P-C (M= Co or Ge) bonding. The ultrasmall size of CoP 2 and GeP 2 nanoclusters provides more active reaction sites and shortens the electron/ion diffusion pathways. The M-P-C bonding bridges phosphide nanoclusters and carbon, changing the interface charge distribution between nanoclusters and carbon polyhedra to promote the reaction kinetics. Additionally, the N,P-doped carbon shells can not only increase the pseudocapacitance contribution by local charge change, but also physically restrain the volume expansion of transition metal phosphides, improving structural stability. The CoP 2 -GeP 2 @NPC heterostructure achieves an exceptional specific capacity exceeding 1600 mAh g -1 and sustain stable cycling for more than 1800 cycles. Notably, the YP80// CoP 2 -GeP 2 @NPC lithium-ion capacitor demonstrates an energy density of up to 124.09 Wh kg -1 , power density of 11.26 kW kg -1 , and cycle life exceeding 10000 cycles. This research provides a viable pathway for achieving rapid kinetic and structural stability in diverse metal phosphide anodes. . Description . N、P co-doped carbon polyhedra with bimetallic nanoclusters embedded by M-P-C bonding for high capacity, high rate and long life lithium-ion capacitors