Microspheric Na₂Ti₃O₇consisting of tiny nanotubes: an anode material for sodium-ion batteries with ultrafast charge–discharge rates

Abstract

Conventionally, rechargeable batteries with a fast charge-discharge rate, while being able to be implemented in large-scale applications with low prices, are critical for new energy storage systems. In this work, first-principles simulations were employed to theoretically investigate the insertion of sodium into the Na(2)Ti(3)O(7) structure. The result discovered that the theoretical capacity of Na(2)Ti(3)O(7) was 311 mA h g(-1). Furthermore, a microspheric Na(2)Ti(3)O(7) material consisting of tiny nanotubes of ca. 8 nm in outside diameter and a few hundred nanometers in length has been synthesized. The galvanostatic charge-discharge measurements, using the as-prepared Na(2)Ti(3)O(7) nanotubes as a working electrode with a voltage range of 0.01-2.5 V vs. Na(+)/Na, disclosed that a high capacity was maintained even under an ultrafast charge-discharge rate. At a current density of 354 mA g(-1), the discharge capacity was maintained at 108 mA h g(-1) over 100 cycles. Even at a very large current density of 3540 mA g(-1), the discharge capacity was still 85 mA h g(-1). HRTEM analysis and electrochemical tests proved that sodium ions could not only intercalate into the Na(2)Ti(3)O(7) crystal, but could also be stored in the intracavity of the nanotubes. All of the results disclose that the as-prepared Na(2)Ti(3)O(7) nanotubes are able to be used as anode materials in large-scale applications for rechargeable sodium-ion batteries at low cost while maintaining excellent performance.

Electrochemical performance of hard carbon negative electrodes for ionic liquid-based sodium ion batteries over a wide temperature range

“…However, when used as the negative electrode in SIBs, graphite is electrochemically inactive, and only a limited number of sodium ions can be intercalated into graphite. [5] In recent years, many materials, including carbonaceous materials, [6][7][8][9][10][11][12][13][14][15] as well as Na 2 Ti 3 O 7 , [16][17][18][19][20] Na 4 Ti 5 O 12 , [21] TiO 2 , [22][23][24] SnO 2 , [25,26] and alloys, [27][28][29][30][31] Moreover, to demonstrate the practical applicability of HC electrode, a full cell was fabricated using NaCrO 2 as the positive electrode, and its performance was investigated for the first time at 90 ºC.…”

Design and Synthesis of Layered Na2Ti3O7 and Tunnel Na2Ti6O13 Hybrid Structures with Enhanced Electrochemical Behavior for Sodium‐Ion Batteries

“…The low Na‐storage voltage not only resulted in a high energy density but also reduced the appearance of sodium dendrite 19. The layered Na 2 Ti 3 O 7 structure was made up of zigzag type layer formed by linking and stacking TiO 6 octahedra ribbon and delivered a high theoretical capacity (177 mAh g −1 ) 20, 21. Nevertheless, one significant deficiency was that the insufficient conductivity, slow ionic mobility, and structural distortion upon Na uptake would severely hinder the development and application of Na 2 Ti 3 O 7 anode in SIBs 15, 22.…”

Synthesis of Single Crystalline Titanium Oxide and Sodium Titanate Nanorods Via Salt-Assisted Ultrasonic Spray Pyrolysis

“…37-0951). This phase is known to be one of the ternary M-Ti-O (M = alkali metal) system materials which have low toxicity, low cost and wide applications including sodium ion batteries and photocatalysts [16][17][18][19]. Although the synthesized nanostructures were not pure TiO 2 but the Na 2 Ti 6 O 13 is also useful and the properties and applications of Na 2 Ti 6 O 13 are quite similar to anatase TiO 2 .…”