Few-layer bismuthene enabled solid-state Li batteries

The issues of slow ionic dynamics and unstable Li/poly(ethylene oxide) (PEO) interface limit the further development of PEO electrolyte. Herein, the integration of bismuthene within PEO electrolyte is designed to enhance the ionic conductivity as the bismuthene weakens the bond strength of O (-EO) and Li+, destroy the crystallization of PEO polymer chain and release more mobility. Density functional theory results also reveal that the diffusion barrier of Li+ is decreased with the incorporation of bismuthene. Li/PEO interface is stabilized by the in-situ formed LixBi-rich layer, validated by XPS and time of flight secondary ion mass spectrometry. The formed LixBi-rich layer modulates the interfacial Li+ cycling process, then restricting the formation of lithium dendrites. The faster ionic transport and enhanced interfacial stability of composite electrolyte enable the Li symmetric battery stable cycling for over 1000 h with the current density of 0.2 mA cm(-2) (50 C). When matching with commercial LiFePO4 or LiNi0.5Co0.2Mn0.3O2, the corresponding solid-state Li batteries exhibit outstanding long-life cycling and rate performance.

Automated summary

The integration of bismuthene into PEO electrolyte enhances ionic conductivity by weakening the bond strength of O (-EO) and Li+, and disrupting the crystallization of PEO polymer chain. The in-situ formed LixBi-rich layer stabilizes the Li/PEO interface and modulates the interfacial Li+ cycling process, thus preventing the formation of lithium dendrites. The composite electrolyte enables stable cycling of Li symmetric battery for over 1000 hours, exhibiting outstanding long-life cycling and rate performance.