Two Steps Li Ion Storage Mechanism in Ruddlesden–Popper Li 2 La 2 Ti 3 O 10

Abstract Innovative anode materials are essential for achieving high‐energy‐density lithium‐ion batteries (LIBs) with longer lifetimes. Thus far, only a few studies have explored the use of layered perovskite structures as LIB anode materials. In this study, the study demonstrates the performance and charge/discharge mechanism of the previously undefined Ruddlesden‐Popper Li₂La₂Ti₃O₁₀ (RPLLTO) as an anode material for LIBs. RPLLTO exhibits two unique voltage plateaus ≈0.6 and 0.4 V(vs Li/Li + ), due to the insertion of lithium ions into different sites within its layered structure. The electrical state of Ti is analyzed using X‐ray photoelectron spectroscopy and X‐ray absorption near edge spectra, revealing a reduction from Ti⁴⁺ to Ti 2 ⁺, corresponding to a capacity of 170 mAh·g⁻¹. In situ X‐ray diffraction patterns and extended X‐ray absorption fine structure spectra demonstrate the crystal structure changes during lithiation. Complementary expansion along the a/b axes and contraction along the c axis result in a volume change of only 4%. This structural stability is evidenced by an 88% capacity retention after 1000 cycles. This study successfully showcases the lithium‐ion storage capability of RPLLTO and contributes to the development of perovskite anode materials with diverse compositions and structures.