Unveiling the Sodium/Potassium Storage Mechanisms of Nanoporous Indium-Bismuth Anode Using Operando X-ray Diffraction

Sodium ion batteries (SIBs) and potassium (PIBs) are promising post-lithium candidates for grid-scale energy storage, understanding of the Na/K chemistry is crucial development advanced electrode materials. Herein, a nanoporous indium-bismuth (np-InBi) alloy was fabricated by chemical dealloying ternary Mg-In-Bi precursor, shows three-dimensional ligament-channel structure. As anode SIBs PIBs, np-InBi exhibits decent initial discharge capacity. More importantly, storage mechanisms were investigated using operando X-ray diffraction (XRD). The XRD results demonstrate that (de)sodiated mechanism in involves (de)alloying processes between InBi + Bi to Na 3 15 In 27 via intermediate products NaBi In. Simultaneously, (de)potassiated PIBs yields reversible ↔ KBi 2 5 K 8 11 .