Crystal structure regulation of trititanium pentoxide for advanced zero-strain lithium storage anode

Significant advancements have been made in electric vehicles and consumer devices. However, lithium-ion batteries with commercial graphite anodes still face challenges owing to their sluggish lithium-ion kinetics, low lithiation potential, and limited cycle stability. Consequently, there is a considerable research interest in developing new anode materials with rich resources, "zero-strain" characteristics for long-term cycling, and outstanding electrochemical properties. In this study, we thoroughly examine the relationship between the structure and electrochemical characteristics of λ and β phases of titanium pentoxides (Ti₃O₅). The findings indicate that the β phase of Ti₃O₅ exhibits a overall electrochemical performance compared to the λ phase. Moreover, β-Ti₃O₅ electrodes deliver a low, yet safe average operating potential of 0.82 V versus Li/Li⁺ and a reversible specific capacity of 181.9 mA h/g at 0.1 A/g, thereby significantly outperforming λ-Ti₃O₅ electrodes, with a value of only 55.7 mA h/g. The performance difference can be primarily attributed to the changes in the crystal structure, with the β phase exhibiting a lower energy barrier for lithium-ion diffusion than the λ-phase. Moreover, the β-Ti₃O₅ electrodes exhibit an good rate performance (capacity retention of 49.5 % at 10 A/g) and good cycling stability (absence of capacity degradation after 2000 cycles at 1.0 A g^-1). These advantages suggest that β-Ti₃O₅ is a promising anode material for reliable, rapid-charging, and secure lithium-ion storage.