NbO2 as a Noble Zero-Strain Material for Li-Ion Batteries: Electrochemical Redox Behavior in a Nonaqueous Solution

Abstract

Lithium-ion batteries are widely available commercially and attempts to extend the lifetime of these batteries remain necessary. The energy storage characteristics of NbO2 with a rutile structure as a material for the negative electrode of lithium-ion batteries were investigated. When negative potential was applied to the NbO2 electrode during application of a constant current in a nonaqueous solution containing lithium ions, these ions were inserted into the NbO2. Conversely, upon application of positive potential, the inserted lithium ions were extracted from the NbO2. In situ X-ray diffraction results revealed that the variation in the volume of NbO2 accompanying the insertion and extraction of lithium was 0.14%, suggesting that NbO2 is a zero-strain (usually defined by a volume change ratio of 1% or less) active material for lithium-ion batteries. Moreover, the highly stable structure of NbO2 allows the corresponding electrode to exhibit excellent cycling performance and coulombic efficiency.

Novel Nonstoichiometric Niobium Oxide Anode Material with Rich Oxygen Vacancies for Advanced Lithium-Ion Capacitors

“…18 It has been recognized that the intrinsic electronic conductivity of the niobium-based oxides is strongly associated with the valence of Nb n+ species (e.g., NbO 2 (tetragonal): ≈10 −4 S cm −1 , T-Nb 2 O 5 : ≈10 −10 S cm −1 ). 18 Moreover, with the decrease of the average valence state of Nb n+ species, the practical reversible capacity of the niobium-based oxides decreases because fewer Li ions can react with Nb−O compounds (e.g., NbO 2 : ≈100 mAh g −1, 19 T-Nb 2 O 5 : ≈200 mAh g −113 ). These facts mean that the strategy of reducing the valence of Nb n+ species would act as a double-edged sword and optimizing the average valence state of Nb 20 In addition to optimizing intrinsic electronic conductivity by introducing low-valence-state Nb n+ species, coating the niobium-based oxides with carbon is another common strategy to counter the low electronic conductivity and minimize the side reactions with liquid electrolytes.…”

Optimization Design and Application of Niobium‐Based Materials in Electrochemical Energy Storage

“…Among them, tetragonal NbO 2 (MP-557057) has been reported as LIC energy storage material. NbO 2 has resistivity %104 Ω cm À1 at room temperature, theoretical capacity 429 mAh g À1 and low lithium embedding/disembedding potential 1.3 V/1.4 V. [16] Jeong [17] used NbO 2 particles deposited in carbon-based materials as LIC cathode materials and investigated the lithium storage mechanism. The reduction peak at 1.5-1.75 V and the oxidation peak at 1.0-1.…”

Zero-strain strategy incorporating TaC with Ta2O5 to enhance its rate capacity for long-term lithium storage

“…This value is less than 1%, verifying that TaC is a zero-strain insertion material. 43 Significantly, the evolution of lattice parameters and volume in the second cycle almost hold constant, testifying to the excellent structural stability and reversibility of TaC. Here, TaC with negligible lattice distortion can confine Ta 2 O 5 in a very limited region, thus giving rise to an enhanced cycling life of the whole anode.…”