C 60 ‐Mediated d‐π Conjugation Induces Electronic Reconstruction to Boost Charge Storage of Nb 2 C/Nb
Mingming Gao, Jundong Shao, Junke Li, Junyi Yang, Ying Huang, Sheng Yang, Faxing Wang, Shunqi Xu, Tanyuan Wang, Xing Lu, Panpan ZhangABSTRACT
Regulating orbital electronic structure to enhance the charge‐storage capability of anode materials is critical for developing high‐performance lithium‐ion hybrid capacitors (LIHCs). Herein, we report a novel interfacial engineering strategy that employs fullerene C 60 ‐mediated d‐π conjugation within a Nb 2 C/Nb 2 O 5 heterostructure (denoted as C 60 ‐Nb 2 C/Nb 2 O 5 ) to realize simultaneous electronic reconstruction and structural optimization. The introduced C 60 forms robust d‐π conjugation with the d ‐orbitals of Nb, acting as an electron acceptor to drive directional charge transfer across both the C 60 /Nb 2 C and Nb 2 C/Nb 2 O 5 interfaces. Combined theoretical and experimental analyses confirm that orbital engineering between Nb ( d xy / d yz ) and C 60 ( p ) facilitates electron backflow, improves intrinsic electronic conductivity, substantially lowers the Li + adsorption barrier, triggers an upward shift of the d ‐band center, and accelerates electron‐transfer kinetics. Consequently, the C 60 ‐Nb 2 C/Nb 2 O 5 anode delivers a remarkable reversible capacity of 658.8 mAh g− 1 at 0.1 A g− 1 and excellent rate capability. The assembled C 60 ‐Nb 2 C/Nb 2 O 5 //activated carbon LIHC achieves a high energy density of 199.5 Wh kg− 1 , ranking among the highest values reported for MXene‐based LIHCs. This work elucidates a molecular‐mediated interfacial electronic engineering mechanism for tailoring charge‐storage behavior, providing a rational design strategy for advanced electrochemical energy‐storage systems.