Work

Wadsley-Roth FeNb11O29 as negative electrode material for lithium solid-state batteries

Year: 2025

Type: article

Abstract: Li-ion solid-state batteries are promising next-generation rechargeable batteries thanks to their high energy density and enhanced safety, but their performance is strongly dependent on the choice of active materials, electrode microstructure and interfacial stability. In this work, the low-strain Wadsley–Roth phase FeNb 11 O 29 is explored as a negative electrode for Li-ion solid-state batteries, benefiting from its open framework for fast Li + transport. Composite electrodes are optimised by tuning the ratio of FeNb 11 O 29 , Li 6 PS 5 Cl solid electrolyte, and vapor grown carbon fibres. The optimal composition can deliver a high-rate capability, achieving ∼210 and ∼80 mAh·g −1 at 0.19 and 1.9 mA cm −2 , respectively, even at a high areal loading of ∼10 mg cm −2 , arising from a balanced electronic and ionic transport. Kinetic limitation of Li + insertion at high rates is identified and can be partly mitigated by end-of-discharge constant-voltage steps. Post-mortem analyses confirm bulk stability of FeNb 11 O 29 and Li 6 PS 5 Cl but revealed an interfacial degradation, with a resistive Li 2 S/oxide-rich interface, consistent with impedance growth. These findings highlight the critical role of microstructural and interfacial optimisation in the electrode composites and establish FeNb 11 O 29 as a promising candidate for high-rate solid-state batteries.

Source: Journal of Power Sources

DOI: 10.1016/j.jpowsour.2025.239120

Authors: Dat Le Thanh, Dominique Foix, Emmanuelle Suard, Romain Berthelot, Long Hoang Bao Nguyen