d-p Orbital Hybridization of Ternary Transition Metal Toward High-Performance Proton Storage
Wei Tu, Ke Mao, Ying Huang, Jundong Shao, Xuan Tian, Pengfei Xu, Sheng Yang, Faxing Wang, Yao Gao, Panpan Zhang*, Xing Lu*
Angew. Chem. Int. Ed. 2025, e202513523
https://doi.org/10.1002/anie.202513523
Abstract
Electrochemical proton storage offers grid-scale energy storage system with long lifespan, great safety, and eco-friendliness. However, preparing proton storage materials with balanced conductivity, activity, and stability remains challenging due to suboptimal structure design. Herein, we report atomic-level engineering of d-p orbital hybridization strategy to regulate transition metal (V/Fe) d-band centers. Vanadium hexacyanoferrate (VHCF)/RuOx quantum dots (RuOxQDs) heterostructure (VHCF–RuOxQDs) was synthesized via in situ co-precipitation. The d-p hybridization of Ru's 4d orbital with VHCF's C≡N 2p orbital (cyano) induces π-backdonation and creates “electronic highways” for regulating the d-electrons of V/Fe, shifting their d-band centers to achieve continuous multi-electron transfer. Moreover, optimizing the d-electron structure reduces the V5+ ratio and thus decreases vanadium dissolution during cycling. The VHCF–RuOxQDs cathode delivers a large capacity of 162 mAh g−1 at 1 A g−1, excellent rate capability (127 mAh g−1 at 40 A g−1), and ultralong stability over 10 000 cycles. When paired with MoO3–MXene anode, the asymmetric full device achieves a high energy density of 53 Wh kg−1 at 1.3 kW kg−1. The atomic-level orbital hybridization regulation of d-electron structure provides a new direction for high-performance proton storage.
