Comprehensive investigation of the lithium insertion mechanism of the Na₂Ti₆O₁₃ anode material for Li-ion batteries

Abstract

Sodium hexatitanate Na2Ti6O13 with a tunnel structure has been proposed to be an attractive anode material for lithium ion batteries because of its low insertion voltage, structural stability and good reversibility.

Towards a Greener and Scalable Synthesis of Na2Ti6O13 Nanorods and Their Application as Anodes in Batteries for Grid‐Level Energy Storage

“…In agreement with the literature, [3,21,38,56] reversible lithium insertion produces two plateaus at 1.3 and at 1.0 V and a broad slope at around 0.8 V (Figure 9c). During the Li extraction process, two plateaus appear at 1.2 and 1.4 V for NTO-900 and NTO-1000, whereas for NTO-1100 only the plateau at 1.3 V is recorded.…”

“…Therefore, the electrochemical insertion of lithium into Na 2 Ti 6 O 13 above 0.6 V can be described by Na 2 (Ti 4+ ) 6 O 13 + x e − + x Li + → Na 2 Li x (Ti 3+ ) 6 O 13 , where the presence of the two plateaus denotes the insertion of lithium ions at two different sites in the tunnel structure. [ 3,23 ] The slope from 0.01 to 0.4 V is ascribed to further lithium intercalation into Na 2 Li x Ti 6 O 13 , which is not reversible. [ 33 ]…”

“…Therefore, the electrochemical insertion of lithium into Na 2 Ti 6 O 13 above 0.6 V can be described by 13 , where the presence of the two plateaus denotes the insertion of lithium ions at two different sites in the tunnel structure. [3,23] The slope from 0.01 to 0.4 V is ascribed to further lithium intercalation into Na 2 Li x Ti 6 O 13 , which is not reversible. [33] The electrodes in sodium assembly (Figure 9d) recover the initial discharge and charge capacities of 122, 112, and 98 mA h g À1 for NTO-900, NTO-1000, and NTO-1100, respectively, with the corresponding coulombic efficiencies of %50-40%.…”

“…Alkali and alkali-earth titanates have recently attracted strong interest due to their excellent physical-chemical properties. In particular, sodium titanates (Na 2 O•nTiO 2 ) have been extensively investigated for application as photocatalysts [1,2] and anode materials for lithium- [3] and sodium-ion batteries (LIBs and SIBs). [4] Although graphite-based materials are desirable in terms of energy density, the formation of a solid electrolyte interphase (SEI) film and the phenomenon of lithium plating lead to serious safety concerns.…”

“…[4] Although graphite-based materials are desirable in terms of energy density, the formation of a solid electrolyte interphase (SEI) film and the phenomenon of lithium plating lead to serious safety concerns. [3] The growth of dendrites causes internal short circuits, resulting in rapid aging or even destruction of the battery. [5,6] In this context, high-potential titanium oxidebased anode materials are expected to overcome these problems due to their inherent high chemical compatibility with the electrolyte.…”