H_0.92K_0.08TiNbO₅ Nanowires Enabling High-Performance Lithium-Ion Uptake

Abstract

HTiNbO5 has been widely investigated in many fields because of its distinctive properties such as good redox activity, high photocatalytic activity, and environmental benignancy. Here, this work reports the synthesis of one-dimensional H0.92K0.08TiNbO5 nanowires via simple electrospinning followed by an ion-exchange reaction. The H0.92K0.08TiNbO5 nanowires consist of many small “lumps” with a uniform diameter distribution of around 150 nm. Used as an anode for lithium-ion batteries, H0.92K0.08TiNbO5 nanowires exhibit high capacity, fast electrochemical kinetics, and high performance of lithium-ion uptake. A capacity of 144.1 mA h g–1 can be carried by H0.92K0.08TiNbO5 nanowires at 0.5 C in the initial charge, and even after 150 cycles, the reversible capacity can remain at 123.7 mA h g–1 with an excellent capacity retention of 85.84%. For H0.92K0.08TiNbO5 nanowires, the diffusion coefficient of lithium ions is 1.97 × 10–11 cm2 s–1, which promotes the lithium-ion uptake effectively. The outstanding electrochemical performance is ascribed to its morphology and the formation of a stable phase during cycling. In addition, the in situ X-ray diffraction and ex situ transmission electron microscopy techniques are applied to reveal its lithium storage mechanism, which proves the structure stability and electrochemical reversibility, thus achieving high-performance lithium-ion uptake. All these advantages demonstrate that H0.92K0.08TiNbO5 nanowires can be a possible alternative anode material for rechargeable batteries.

Layered Potassium Titanium Niobate/Reduced Graphene Oxide Nanocomposite as a Potassium-Ion Battery Anode

“…Only after the plateau does the Nb significantly oxidise. Finally, full charging to 3 V still resulting in the contributions from Ti 3+ and Nb 4+ indicating that not all the intercalated K + is able to de-intercalate, with this partial irreversibility being previously reported [ 19 , 22 , 34 ]. This is likely a contributor of the discrepancy between the theoretical capacity and the observed capacity, as a partial re-oxidation will leave K + remaining in the structure, rendering it electrochemically inactive.…”

“…By 20 cycles this had dropped to 60.6 mAh g −1 , a 66.9% drop. The capacity is also higher than previously reported (50 mAh g −1 ) and is believed that this increase is due to the nanoparticle morphology, as the number of available ionic channels is drastically increased, resulting in greater intercalation and reduced polarization [ 34 , 55 ]. However, this increase in surface area also results in more irreversible processes like side reactions with the electrolyte, forming more SEI, as noted from the low initial Coulombic efficiency (ICE) of 39%.…”

“…It additionally has a particularly large d -spacing of 0.94 nm allowing for the easy intercalation of charge carrying species [ 31 , 32 ]. This large d spacing is primarily the reason for the use of KTNO in previous work, as it has been ion-exchanged with H + to boost storage in LIBs and Na-ion batteries (NIBs), or to exfoliate it into TNO nanosheets [ 28 , 33 , 34 ]. KTNO has been tested as a baseline material, but no work has focused on it as a primary material.…”

Nb-Based Mixed Oxides As Anodes for Metal-Ion Capacitors: Progress, Challenge, and Perspective

“…presented a novel layered titanoniobate (HTi 2 NbO 7 ) applied for sodium storage (Figure e). Unlike ANb 2 O 6 , froodite SnNb 2 O 6 is composed of Sn 2+ ions and double-layered octahedral NbO 6 units built by edge-sharing octahedral NbO 6 units, which have been reported to store lithium. , H 0.92 K 0.08 TiNbO 5 , Sn 2 Nb 2 O 7 , CsTi 2 NbO 7 , Ti 0.61 Nb 1.29 O 4 , Ti 0.75 Nb 0.25 O 2 , , Ti 2 Nb 2 O 9 , , and K 4 Nb 6 O 17 (KNO) − were reported as well in previous studies. In general, these structures provide a large number of ion intercalation sites and is a potential ideal anode material.…”

A3Ti5NbO14 (A = H, Li and K) family: ionic exchange, physical and electrochemical properties

“…8 This layered lithium niobium titanate showed a promising performance with a specific charge of 245 mA h g −1 at 1.4 V. Additionally, a mixed hydrated phase incorporating potassium, Li 0.55 K 0.45 TiNbO 5 •H 2 O, obtained from sol-gel synthesized KTiNbO 5 through an ion-exchange method, demonstrated stable and satisfactory battery performance over 100 cycles, especially at very low voltages 0.2 V. 9 The exploration continued with the development of H 0.92 K 0.08 TiNbO 5 nanowires in 2019. Produced via electrospinning followed by an ionexchange reaction, this 1D morphology exhibited fast electrochemical kinetics, achieving a capacity of 144.1 mA h g −1 at 0.5 C. 10 Another compound, with the Ti 2 Nb 2 O 9 formula initially reported in 2008, 11 was revisited in 2021 and achieved a highly reversible capacity of 200 mA h g −1 with an average potential of 1.5 V vs. Li/Li + . This compound was synthesized from HTiNbO 5 , using NH 4 TiNbO 5 as a precursor, which was then annealed to produce the Ti 2 Nb 2 O 9 sample.…”