Synthesis and electrochemical properties of spinel Li4Ti5O12−x Cl x anode materials for lithium-ion batteries

Abstract

Li 4 Ti 5 O 12−x Cl x (0 ≤ x ≤ 0.3) compounds were synthesized successfully via high temperature solidstate reaction. X-ray diffraction and scanning electron microscopy were used to characterize their structure and morphology. Cyclic voltammetry, electrochemical impedance spectroscopy, and charge/discharge cycling performance tests were used to characterize their electrochemical properties. The results showed that the Li 4 Ti 5 O 12−x Cl x (0≤x≤0.3) compounds were well-crystallized pure spinel phase and that the grain sizes of the samples were about 3-8 μm. The Li 4 Ti 5 O 11.8 Cl 0.2 sample presented the best discharge capacity among all the samples and showed better reversibility and higher cyclic stability compared with pristine Li 4 Ti 5 O 12 . When the discharge rate was 0.5 C, the Li 4 Ti 5 O 11.8 Cl 0.2 sample presented the superior discharge capacity of 148.7 mAh g −1 , while that of the pristine Li 4 Ti 5 O 12 was 129.8 mAh g −1 ; when the discharge rate was 2 C, the Li 4 Ti 5 O 11.8 Cl 0.2 sample presented the discharge capacity of 120.7 mAh g −1 , while that of the pristine Li 4 Ti 5 O 12 was only 89.8 mAh g −1 .

Plasma Processing of Electrospun Li‐Ion Battery Separators to Improve Electrolyte Uptake

“…[8,9] In particular, non-woven electrospun coating of commercial separators [10,11] and electrospun separators [12][13][14][15][16] have been widely studied for their unique properties, such as extremely high surface-to-volume ratio, high degree of porosity, and pore interconnectivity. Such properties are strongly linked to separator performance, since membrane porosity permits Li-ions transport and minimizes the ionic resistance, thus reducing the electrical cell resistance [17][18][19][20] and improving energy density per weight. [21] Furthermore, their porous structure enables high electrolyte uptake, which decreases the electrolyte leakage.…”

A lithium-ion battery separator prepared using a phase inversion process

“…The pore diameter was less than 1 micron when more than 0.25 parts of silica were added. This successfully meets the USABC requirement that the pore size should be smaller than 1 micron [19]; yet compared with the tens of nanometer-sized pores in a commercial separator, the pore diameters in these membranes are relatively big. It is valuable to investigate in further whether sub-micron pores would increase the risk of battery failure due to internal shorting, especially under abuse operating conditions.…”

“…Although improved ionic conduction has been observed, the mechanical strength of these macroporous membranes needs to be improved. The United States Advanced Battery Consortium (USABC) has set its requirement on the separator tensile property as being less than 2% offset strain at 6.9 MPa (1000 psi) [19,20]. In addition, PVDF loses its mechanical strength in a liquid electrolyte, especially when the temperature is high, which may result in an increased risk of electric short when highly porous PVDF membranes are used as separators.…”

Solution‐Based, Anion‐Doping of Li4Ti5O12 Nanoflowers for Lithium‐Ion Battery Applications

“…Nevertheless, for anion doping, [11,[13][14][15][16][17][18][19][20] relatively little work has been previously reported in this field as compared with cation doping, [6,12,21,22] possibly due to the limited choices of anion dopants. Even so, this compound can be readily doped with halides, as implied by the increased number of O 2sites (12) as compared with the corresponding Ti + (5 sites) and Li + (4 sites).…”