Partially Reduced Titanium Niobium Oxide: A High‐Performance Lithium‐Storage Material in a Broad Temperature Range

Abstract

The existing electrode materials for lithium-ion batteries (LIBs) generally suffer from poor rate capability at low temperatures, severely limiting their applications in winter and cold climate area. Here, partially reduced TiNb 24 O 62 (PR-TNO) are reported that demonstrates excellent electrochemical performance in a broad temperature range, notably at low temperatures. Its crystal structure is similar to that of Ti 2 Nb 10 O 29 upon partial reduction in H 2 . The titanium and niobium ions in PR-TNO enable multielectron transfer, safe operation, and high Coulombic efficiencies. Benefiting from the increased electronic conductivity of the partially reduced phase and its robust crystal structure with a large interlayer spacing, PR-TNO shows fast electron and Li + transport, small volume change associated with Li + storage, and notable capacitive behavior, resulting in good electrochemical performance even at very low temperatures. At −20 °C, a large reversible capacity of 313 mAh g −1 is obtained at 0.1C, reaching 83.3% of that at 25 °C. At 5C, high rate capability (58.3% of that at 0.5C) is achieved, only slightly lower than that at 25 °C (60.7%). Furthermore, PR-TNO demonstrates excellent cyclic stability with 99.2% of the initial capacity after 1680 cycles, confirming its excellent suitability for low-temperature LIBs.

Conductive LaCeNb6O18 with a Very Open A‐Site‐Cation‐Deficient Perovskite Structure: A Fast‐ and Stable‐Charging Li+‐Storage Anode Compound in a Wide Temperature Range

“…Moreover, the volume change and structure evolution of LCNO during lithiation are further studied by in situ TEM technology. [13] The strain fringes caused by the Li + insertion into the LCNO lattice and phase transformation exhibit significant movement throughout the tested particle, but the morphology and volume changes are very small, as expected (Figure 6d,e; Video S1, Supporting Information). In addition, the in situ HRTEM image and in situ SAED pattern after lithiation reveal very limited changes (Figure 6f), which verifies the small changes of the lattice constants.…”

“…In Situ Examinations: In situ XRD tests were conducted based on specially designed modules (LIB-XRD and LIB-LHTXRD-LN for the tests at 25 and 60 °C, respectively, Beijing Scistar Technology), in which Be plates served as not only the X-ray transmission windows but also the current collectors, and glass-fiber films (GF/D-1823, Whatman) served as the separators. [13,16] In situ XRD spectra were recorded during GCD at 0.4 C. An in situ XRD experiment at 60 °C was performed with a homemade temperature-control device. The LIB-LHTXRD-LN module was covered by a polyetheretherketone (PEEK) dome for controlling the high temperature.…”

“…The XPS peaks located at 210.5 and 207.8 eV (Figure 4a) correspond to the Nb-3d 3/2 and Nb-3d 5/2 of Nb 5+ , respectively. [13] At the discharge state (0.8 V, Figure 4b), besides the peaks at 210.5 and 207.8 eV for Nb 5+ (29%), the peaks at 208.8 and 206.1 eV are attributed to Nb 4+ (33%), and the peaks at 206.9 and 204.2 eV are ascribed to Nb 3+ (38%). [14] After the charge state (3.0 V, Figure 4c), the valence of Nb significantly recovers, obtaining a combination of Nb 5+ (91%) and Nb 4+ (9%).…”

Boosting Lithium Storage of a Metal-Organic Framework via Zinc Doping

“…The commercial anode material graphite, which can be easily produced, is limited by an insufficient capacity of 372 mA h g −1 [4]. Other types of anode materials such as alloy [5,6] and conversion reaction-based transition metal oxides [7,8] possess ultrahigh specific capacity. Nevertheless, the dramatic volume expansion during the charge/discharge process and poor cycle performance restrict the broad use of those materials.…”

Wadsley-Roth Phase Niobium-Based Oxide Anode Promising High Power and Energy Density Aqueous Li-Ion Batteries

“…Cyclic voltammetry (CV) plots of Zn 2 Nb 34 O 87 tested in 1 M LiPF 6 nonaqueous electrolytes and WiBS electrolytes at a scanning rate of 0.1 mV s –1 are presented in Figure f. The CV profile in nonaqueous electrolytes presents redox peaks at about 1.83/1.55 V and 1.28/1.20 V vs Li/Li + , corresponding to the redox reactions of Nb 5+ /Nb 4+ and Nb 4+ /Nb 3+ , respectively. ,, Since the electrochemical window of the WiBS electrolyte is restricted to 1.65 V vs Li/Li + , only the Nb 5+ to Nb 4+ oxidation–reduction reaction occurs in the WiBS electrolyte, which corresponds to the redox peak pair of 2.04/1.93 V vs Li/Li + . Because of its high salt concentration, the average redox potential of M–Nb–O has a Nernst shift of approximately 0.3 V between the nonaqueous electrolyte (1.69 V vs Li/Li + (1.83 V + 1.55 V)/2) and the WiBS aqueous electrolyte (1.99 V vs Li/Li + , (2.02 V + 1.93 V)/2), which means the cathodic limit of this WiBS aqueous electrolyte can be expanded to 1.35 V vs Li/Li + .…”