Combustion synthesis as a low temperature route to Li₄Ti₅O₁₂ based powders for lithium ion battery anodes

Abstract

(LTO) is considered as a promising anode material for lithium ion batteries due to its high stability and its inherent safety. Since LTO is typically synthesized at high temperatures, a study of combustion synthesis of LTO is presented, wherein effects of oxidizer amount in the precursor and atmosphere during thermal decomposition are investigated. Combustion synthesis implies heating a precursor to a relatively low process temperature, after which the system generates the necessary energy for complete conversion and crystallization to the desired oxide. Hereto, the precursor and thermally treated powders were characterized by thermogravimetric analysis (TGA) coupled with differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), cyclic voltammetry (CV) and galvanostatic cycling. The study shows that the combustion process allows the synthesis of LTO at process temperatures as low as 300 C, compared to around 800 C for solid state reactions and sol-gel routes. The product consists of crystalline LTO with minor impurities. The product was used as an electrode material in a lithium battery coin cell and demonstrated a high stability and a capacity of 164 mA h g À1 at 0.1C and 132 mA h g À1 at 2C. This paper shows that combustion synthesis can considerably lower the temperature required for the synthesis of ceramic materials, after careful optimization of the precursor, since the mechanism of thermal degradation is complex and dependent on a large number of parameters.

Understanding the Behaviors of λ-MnO2 in Electrochemical Lithium Recovery: Key Limiting Factors and a Route to the Enhanced Performance

“…The sizes of LiMn 2 O 4 particles analyzed by dynamic light scattering (DLS) measurement appeared at two different ranges: below 10 and 100−300 μm, as depicted in Figure S1c. Given that the signals from relatively large sizes can be presumed as originating from collective behaviors of lumps of particles, 44 the average of particle sizes was calculated from the relatively smaller range of the size distribution, and the result was 3700 ± 877 nm. A silver electrode prepared by using silver powders and polymeric binders was used as the counter electrode for Cl − capture and release (see the Experimental Section for detailed procedures).…”

Fabrication of Li4Ti5O12 (LTO) as Anode Material for Li-Ion Batteries

“…Temperature-programmed oxidation experiments demonstrate that cellulose thermal pyrolysis creates a reducing atmosphere, which may facilitate oxygen-ion diffusion. In the combustion process performed by De Sloovere and co-workers [ 100 ], the Ti precursor was prepared using lactic acid added to the hydrated titanium hydroxide in a 3:1 molar ratio in aqueous solution. Then, the mixture was refluxed at 80 °C for complete dissolution and adjusted at a pH of ~6.8 by the addition of ammonia (35%).…”

“…Hirayama et al [496,497] fabricated epitaxial Li 4 Ti 5 O 12 thin-films deposited on SrTiO 3 single-crystal substrates with (111), (110), and (100) lattice plane orientations using a PLD apparatus equipped with a KrF excimer laser with a wavelength of 248 nm under O 2 atmosphere. LTO films have the same orientation as the SrTiO 3 substrates: Li 4 Ti 5 O 12 (111) on SrTiO 3 (111), Li 4 Ti 5 O 12 (110) on SrTiO 3 (110), and Li 4 Ti 5 O 12 (100) on SrTiO 3 (100). These epitaxial films contained island structures, and the morphologies of the ( 111), (110), and (100) films exhibit angular, needle-like, and circular shapes, respectively.…”

“…Recently, the same group [484] used Li4Ti5O12 and targets simultaneously in confocal configuration to sputter LTO epitaxial films at a p [501] reported the growth of epitaxial, single-crystal, strain-free LTO thin films (150 nm thick) deposited by PLD on MgO (111) single-crystal substrate at 500 • C in an oxygen atmosphere at a pressure of 1.7 Pa. A KrF excimer laser (λ = 248 nm) was employed at a fluence of 2.6 J cm −2 and a frequency set at 10 Hz. For comparison, polycrystalline LTO film, representing a nonideal system including grain boundaries, was deposited on a sput-tered polycrystalline MgO film on Si (100). In a second publication, the target for PLD was prepared by mixing and grinding Li 2 CO 3 and TiO 2 rutile to obtain an overlithiated target with a composition of Li 5.35 Ti 5 O 12 .…”

Glycine-Nitrate Process for Synthesis of Na3V2(PO4)3 Cathode Material and Optimization of Glucose-Derived Hard Carbon Anode Material for Characterization in Full Cells

“…Thirdly, this method can be turned into a flow process, which makes it industrially scalable [13]. The GNP and its variations have been used by the solid-oxide fuel cell research community [13,17,18] and to some extent by the battery community to synthesize and study materials like NaTi3(PO4)3 [19], Li(Ni1/3Mn1/3Co1/3-xNax)O2 [20], LiNi1/3Co1/3Mn1/3O2 (urea as fuel) [21], Li4Ti5O12 (lactic acid as fuel) [22], substituted Na0.44MnO2 bronzes [23][24][25][26], Na0.44MnO2 (urea as fuel) [27] and ZnFe2O4 [28]. This paper is the first report to our knowledge that successfully utilizes the GNP method to produce a NVP cathode material and characterize it in half and full cells.…”