Tuning the Position of the Redox Couples in Materials with NASICON Structure by Anionic Substitution

Previous studies on insertion of lithium into rhombohedral forms of and have determined the position of the redox couple to be at 3.6 and 2.8 eV, respectively, below the Fermi level of lithium. Lithium insertion into rhombohedral with NASICON framework exposes the redox couple at 3.3–3.4 eV below the Fermi energy of lithium. Unlike , the insertion of lithium into the structure of is accomplished as a single‐phase solid solution, which makes it attractive as an electrode material for rechargeable lithium batteries.