Enhanced High-Rate Capability of Iodide-Doped Li4Ti5O12 as an Anode for Lithium-Ion Batteries

Abstract

Li4Ti5O12 (LTO) is an alternative anode material to substitute commercial graphite for lithium-ion batteries due to its superior long cycle life, small volume change (zero strain), good thermal stability, and relatively high power. In this work, iodide-doped LTO is prepared by solid-state reaction method via ball milling method and subsequently calcined at 750 °C for 10 h in air atmosphere. X-ray diffraction (XRD) of iodide-doped LTO reveals the spinel cubic structure without any impurities detected. The 0.2 mol lithium iodide-doped LTO shows enhanced high-rate capability with a specific discharge capacity of 123.31 mAh g−1 at 15 C. The long cyclic performance of 0.2 mol lithium iodide-doped LTO delivers a specific discharge capacity of 171.19 mAh g−1 at 1 C with a capacity retention of 99.15% after 100 cycles. It shows that the iodide-doped LTO is a promising strategy for preparing a high electrochemical performance of LTO for the anode of lithium-ion batteries.

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

“…This I-doped LTO delivered a capacity of 123 mAh g −1 at 15C. At 1C, the cell delivered a discharge capacity of 171 mAh g −1 with a capacity retention of 99.15% after 100 cycles [ 525 ]. Synergetic effects can be obtained by the synthesis of composites made of doped LTO and a conductive material.…”

Mixed anion effects on structural and electrochemical characteristics of Li4Ti5O12 for high-rate and durable anode materials

“…Other reports have also shown that halide-ion-substituted LTOs have higher specic capacities than pristine LTOs, although only below the theoretical capacity. [30][31][32][33][34][35][36][37] Furthermore, the capacity reduction in F-LTO, as compared to Cl-LTO may stem from slightly degraded electronic conductivity, which can be attributed to the strong electronegativity of uorine.…”

“…Furthermore, many fundamental studies have been carried out on cationsubstitution effects, [19][20][21][22][23][24][25][26][27][28][29]38 but there are only a few reports on mixed-anion effects. [30][31][32][33][34][35][36][37][38] Therefore, determining the full picture for mixed-anion effects of spinel lithium titanate systems provides new methods for material design that overcome the current performance limitations. We believe that LTO contained in batteries implemented so far has been used with a lower active material weight ratio and further limited to a very narrow state of charge (SOC) range to avoid the above gas evolution problem and low electronic conductivity problem.…”

“…In the literature, transition metals are doped into cationic sites, such as Mg 2+ , 19 Ca 2+ , 20 Zn 2+ , 21 Cr 3+ , 22 Al 3+ , 23 La 3+ , 24 Zr 4+ , 25 V 5+ , 26 Nb 5+ , 27 Ta 5+ , 28 and Mo 5+ , 29 or anions, such as Br − , 30 N 3− , 31 Cl − , 32 F − , 33–36 or I − . 37 For example, doping with divalent Mg ions leads to the reduction of Ti 4+ to Ti 3+ , enhancing conductivity. 38 The formation of mixed-valence Ti 4+ /Ti 3+ can also be achieved through self-doping with Ti 3+ or by creating oxygen vacancies, which improve the intrinsic conductivity of LTO without introducing impurities.…”