Synthesis and electrochemical properties of lithium zinc titanate as an anode material for lithium ion batteries via microwave method

Abstract

Lithium zinc titanate (Li2ZnTi3O8) anode material has been synthesized via a microwave method for the first time.

Reversible Movement of Zn2+ Ions with Zero-Strain Characteristic: Clarifying the Reaction Mechanism of Li2ZnTi3O8

“…Common electrochemical features have been observed in Li 2 ZnTi 3 O 8 : − the voltage vs Li + /Li gradually decreases to ∼0.7 V up to a Q dis value of ∼50 mAh·g –1 , then maintains a constant value at ∼0.6 V until ∼150 mAh·g –1 , and finally decreases gradually again to ∼0.2 V. The subsequent charge (oxidation) curve is quite different from the previous discharge curve; i.e., a plateau appears at ∼1.5 V in the Q cha range between 50 and ∼150 mAh·g –1 . The difference between the voltages of the discharge and charge curves appears in further extended cycles without any significant capacity fading. − The origins of the voltage hysteresis are not yet fully understood, although many studies have been devoted to improving the electrochemical properties of Li 2 ZnTi 3 O 8 , such as research on new synthetic routes, − surface modifications, , and doping/substitution with other elements. − …”

“…Lithium zinc titanium oxide Li 2 ZnTi 3 O 8 has attracted a great deal of attention as a negative electrode material for LIBs because of its large rechargeable capacity ( Q recha ) of more than 170 mAh·g –1 . − Figure a schematically shows the crystal structure of Li 2 ZnTi 3 O 8 , which crystallizes into cubic spinel in which Li + and Zn 2+ ions are randomly distributed in the tetrahedral (tet) sites, while Li + and Ti 4+ ions order in a 1:3 ratio in the octahedral (oct) sites, resulting in a cation distribution of (Li 1/2 Zn 1/2 ) tet [Li 1/2 Ti 3/2 ] oct . − The crystal structure of Li 2 ZnTi 3 O 8 is assigned to the P 4 3 32 (or P 4 1 32) space group. − …”

K-doped Li2ZnTi3O8/C as an efficient anode material with high performance for Li-ion batteries

“…6, the charge-transfer resistance of the Li 1.9 K 0.1 ZnTi 3 O 8 /C was found to be lower than that of Li 2 ZnTi 3 O 8 / C, demonstrating low-dose K + doping to be a useful method for enhancing the electronic conductivity. 46,47 In addition, according to the data in the low-frequency regions, the Li + diffusion rate of the Li 1.9 K 0.1 ZnTi 3 O 8 /C sample was slightly higher than that of the Li 2 ZnTi 3 O 8 / C sample.…”

Cr-Doped Li2ZnTi3O8 as a High Performance Anode Material for Lithium-Ion Batteries

“…The semicircle in the high-frequency regions is associated with charge transfer resistance on the electrode/electrolyte interface, while the straight line in the low-frequency regions is ascribed to the diffusion of Li + into the Warburg resistance (Long et al, 2011 ; Tang et al, 2019 ), which constitutes the bulk of the electrode materials. It is clear that the charge transfer resistance of the Li 2 ZnTi 2.9 Cr 0.1 O 8 electrode material is lower than that of Li 2 ZnTi 3 O 8 , showing that a certain small amount of Cr 3+ doping of Li 2 ZnTi 3 O 8 is useful for enhancing the electronic conductivity (Li Z. F. et al, 2016 ; Kou et al, 2020 ). In addition, the slope for the Li 2 ZnTi 2.9 Cr 0.1 O 8 electrode material in the low-frequency regions is slightly higher than that for Li 2 ZnTi 3 O 8 because Cr doping can strengthen lithium ion migration through Li 2 ZnTi 3 O 8 .…”

“…Recently, there have been numerous studies of anode materials, including LiTi 2 O 4 , Li 2 Ti 3 O 7 , Li 2 Ti 6 O 13 , Li 4 Ti 5 O 12 , Na 2 Li 2 Ti 6 O 14 , TiNb 2 O 7 , and Li 2 ZnTi 3 O 8 (Tang et al, 2014a ; Chen B. K. et al, 2015 ; Li G. H. et al, 2016 ; Liu et al, 2016 ; Li Z. F. et al, 2016 ; Yi et al, 2020b ). Li 2 ZnTi 3 O 8 with the cubic spinel structure has been considered as a promising material because of its lack of toxicity, low cost, relatively high theoretical capacity of 227 mA h g −1 , and its low discharge voltage plateau of ~0.5 V (vs. Li/Li + ) (Jović et al, 2009 ; Chen B. K. et al, 2015 ; Chen W. et al, 2015 ).…”