Interfacial space charge design with desired electron density to enhance sodium storage of MoS2@Nb2O5 anode
Xin Xu, Stuart Jacob Robertson, Tao Yang, Fuzhou Chen, Xinhua Geng, Yanjun Wang, Ji Feng, Changlong Sun, Shengzhou Chen, Minhua Shao, Jiahai Wang
Abstract
The interfacial effect is crucial for achieving superior sodium-ion storage performance in MoS 2 -based anodes. In this study, we constructed an interfacial effect by hydrothermally synthesizing Nb 2 O 5 nanoparticles on MoS 2 nanosheets (MoS 2 @Nb 2 O 5 ). XPS analysis confirms a significant chemical interaction between MoS 2 and Nb 2 O 5 through interfacial covalent bonding (Mo-S/Nb-O) which enhances interatomic electron migration. Electrochemical kinetic analysis indicates an increased pseudocapacitance contribution. The galvanostatic intermittent titration technique (GITT) analysis shows improved charge transfer kinetics. Ex-situ XPS results reveal the reversible intercalation/deintercalation and oxidation/reduction mechanisms of the MoS 2 @Nb 2 O 5 anode. Density functional theory (DFT) results show that strong interfacial bonding significantly enhances electrochemical reaction kinetics. The discharge capacity of the MoS 2 @Nb 2 O 5 anode reaches up to 414.5 mA h g −1 at 0.1 A g −1 after 200 cycles, and the capacity retention is approximately 97.5 % at 2.0 A g −1 after 1000 cycles, demonstrating good rate capability and capacity retention. This in-situ interfacial construction strategy presents an effective approach to designing MoS 2 -based anodes with improved electrochemical performance .