1️⃣ Introduction to Lithium Titanate Anode Material

Lithium titanate is a white powder at room temperature, with the molecular formula Li. ₄ Ti ₅ O ₁₂ , is a composite oxide composed of metallic lithium and a low-potential transition metal—titanium, and it is Li ₂O-TiO₂ A stable spinel in the series (2Li ₂O-5TiO₂ ) Structure: face-centered cubic, space group Fd3m, with a unit-cell parameter of 0.836 nm. Oxygen atoms are arranged in a cubic close-packed configuration at the 32e positions; three-quarters of the Li ions occupy the tetrahedral 8a sites, while Ti and the remaining Li ions are randomly distributed over the octahedral 16d sites. Consequently, the molecular formula of lithium titanate can also be expressed as [Li] _8a [Li _{One third} Ti _5/3 ]_16d [O ₄ ]_32e , belongs to AB ₂ X ₄ A series of spinel-type solid solutions. Lithium titanate has a theoretical specific capacity of 175 mAh/g, and its practical specific capacity exceeds 160 mAh/g, making it one of the currently commercialized anode materials.

Figure 1: Lithium titanate (Li ₄ Ti ₅ O ₁₂ ) Diagram of atomic structure

2️⃣ Unique advantages of lithium titanate anode materials:

(1) The “zero-strain” characteristic of the crystal structure at different lithiation states results in high electrochemical stability and an exceptionally long cycle life.

       Graphite anode materials possess a two-dimensional layered structure, and during lithium‑ion insertion or extraction, they undergo volume expansion and contraction of approximately 5%–8%. With repeated cycling, the graphite anode gradually delaminates from the current collector and flakes off, leading to reduced battery stability and a significant shortening of cycle life. In contrast, lithium titanate anode materials adopt a spinel structure; during lithium‑ion deintercalation, their crystal lattice experiences a volume change of less than 0.3%, effectively exhibiting “zero strain.” This minimizes structural collapse and electrode detachment caused by volume fluctuations during charge–discharge, thereby achieving… Lithium titanate battery High electrochemical stability and an ultra-long cycle life.

Figure 2: Schematic illustration of structural transformations during lithium insertion and extraction in graphite and lithium titanate anodes.

(2) High delithiation potential, no SEI film or lithium dendrite formation, resulting in a high safety margin.

The lithium‑intercalation potential of graphite anodes is typically below 0.2 V, while the lithium deposition potential is around 0 V; these two potentials are quite close. Consequently, during lithiation, a solid electrolyte interphase (SEI) film readily forms on the graphite surface, resulting in relatively low first-cycle coulombic efficiency (91–95%). During cycling, the SEI continuously repairs itself and gradually thickens, hindering further lithium ion insertion and promoting the formation of metallic lithium dendrites on the graphite surface. An increasing density of these dendrites can pierce the separator, leading to internal short circuits and posing significant safety risks.

Lithium titanate has a lithium‑ion potential of 1.55 V, exhibits no solid–electrolyte interphase (SEI) formation during charge–discharge cycling, boasts a high first-cycle coulombic efficiency (97–99%), poses no risk of lithium plating, and offers a high safety margin.

Figure 3: Comparison of the Structures of Conventional Lithium-Ion Batteries and Lithium Titanate Batteries

(3) Spinel structure with three-dimensional fast ion transport channels, enabling high-rate charge–discharge performance.

Lithium titanate has a spinel structure, in which each octahedral vacancy is coordinated by eight neighboring oxide ions, and the center of each octahedron contains a vacancy occupied by a lithium ion, forming an octahedral arrangement. This structural motif endows lithium titanate with excellent three-dimensional ionic transport properties; its intercalation spacing is significantly larger than the graphite layer spacing (0.335 nm). The ionic conductivity of the lithium titanate negative electrode is 10… ^-8 centimeter ² /S, which is significantly higher than the ionic conductivity of graphite anodes (10 ^-10 -10 ^-11 centimeter ² /S), enabling high-rate charge–discharge performance.

Figure 4: Comparison of the Structures of Graphite and Lithium Titanate Anodes

Figure 5: Li ₄ Ti ₅ O ₁₂ Charge–discharge curves of the negative electrode material at different C-rates.