Ambient-Pressure Solvothermal Synthesis of Highly Mn-Doped Titania and Its Behavior as an Anode in Lithium-Ion...

Over the past few decades, battery research has increasingly focused on titanium dioxide (TiO₂) and manganese dioxide (MnO₂), with TiO₂ commonly used as an anode material and MnO₂ as a cathode, due to their stability, abundance, and low cost. In this study, a novel TiO₂-based material doped with high manganese (Mn) content was synthesized via a high-temperature solution-phase synthesis method using a single-source precursor for application in lithium-ion batteries (LIBs). The synthesis was conducted under controlled conditions, achieving high Mnⁿ⁺ cation doping levels of up to 20-25 mol %, leading to previously unreported changes in the material's electrochemical performance. A temperature-dependent phase transformation from anatase to rutile was observed. Samples with 5 mol %, 20 mol %, and 50 mol % Mnⁿ⁺-ion doping were prepared and investigated for their structural, morphological, and electrochemical characteristics. Characterization techniques included X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and cyclic voltammetry (CV). The doped materials exhibited properties distinct from those of pure TiO₂ and pure MnO₂, indicating effective Mn incorporation into the TiO₂ lattice. This study highlights the potential of high-Mn-content TiO₂-based materials as next-generation anode candidates for LIBs while also revealing the performance limitations associated with excessive Mn doping. The resulting insights into the chemistry of Ti-Mn mixed oxide anodes demonstrate the strong link between molecular precursor design and the resulting phase composition and structure. The latter is directly related to the electrochemical performance, offering a better understanding for future design and engineering of next-generation mixed oxide electrodes.