Three-Dimensional and Mesopore-Oriented Graphene Conductive Framework Anchored with Nano-Li₄Ti₅O₁₂ Particles as an Ultrahigh Rate Anode for Lithium-Ion Batteries

Abstract

Because of the disadvantages of commercial graphite anodes for high-power lithium-ion batteries, a kind of spinel nanolithium titanate (Li 4 Ti 5 O 12 )/graphene microsphere composite [denoted as LTO/reduced graphene oxide (rGO)] is successfully synthesized. The as-prepared composite is made up of curled graphene sheets which are anchored with nano-Li 4 Ti 5 O 12 particles. These nano-Li 4 Ti 5 O 12 particles are uniformly decorated on the conductive graphene framework and their sizes range from just 15 to 20 nm. In the asprepared composite, the curled graphene sheets form a unique mesopore-oriented structure which provides plenty of threedimensional channels for ion transportation. These structure characters greatly improve both the electron conductivity and Li + diffusion ability. The ratio of pseudocapacitive capacity dramatically increases in the obtained LTO/rGO composite and generates excellent ultrahigh rate performances. The as-prepared LTO/rGO composite delivers a reversible capacity of 70.3 mA h g −1 at 200 C and a capacity retention of 84.7% after 1000 cycles at 50 C. As the current density varies from 30 to 100 C, the special capacity remains unchanged (about 112 mA h g −1 ). These results show that the graphene framework-supported nano-Li 4 Ti 5 O 12 composite has potential application in high-power lithium-ion batteries.

Nanosheet-assembled hierarchical Li4Ti5O12 microspheres for high-volumetric-density and high-rate Li-ion battery anode

“…A very flat plateau with two sloping regions (at 2.5-1.5 V and 1.5-1.0 V vs Li þ /Li) was observed in all three samples. The flat plateau at about 1.55 V contributes to the majority of the total capacity, showing the inherent feature of a two-phase reaction based on the Ti 4þ /Ti 3þ redox couple [50]. At the low current rate of 1 C, the three electrodes all deliver a stable specific capacity of about 175.0 mAh g À1 , which is close to the theoretical capacity of LTO [51].…”

Low-cost and environmentally friendly synthesis of an Al3+and Mn4+co-doped Li4Ti5O12composite with carbon quantum dots as an anode for lithium-ion batteries

“…To promote the process of commercial application, numerous research studies have been conducted to improve the performance of LTO, including nano-sized synthesis, [8][9][10] coating a second phase with high capacity or conductivity such as Ag, Cu, or carbon, [11][12][13][14][15][16] and doping with ions such as Na + , Mg 2+ , Fe 3+ , Ag + , Zn 2+ and F À in Li, Ti, or O sites. [16][17][18][19] To our knowledge, the ionic radii of Al 3+ and Mn 4+ are approximately equal to Ti 4+ .…”

A synergistic effect of lithium titanate/pristine graphene composite with enhanced lithium storage capability

“…To surmount the above obstacles, fabricating a composite of Li 4 Ti 5 O 12 with a conductive second phase is a valid method to heighten the electronic conductivity of Li 4 Ti 5 O 12 . The conductive second phase includes carbon, 13,14 carbon nanotube, 15,16 and graphene 17,18 . Li 4 Ti 5 O 12 particles can be closely attached to the surface of the conductive second phase, which is beneficial to the transfer of the electron 19 .…”

“…The conductive second phase includes carbon, 13,14 carbon nanotube, 15,16 and graphene. 17,18 Li 4 Ti 5 O 12 particles can be closely attached to the surface of the conductive second phase, which is beneficial to the transfer of the electron. 19 Among these conductive second phases, graphene has become the most popular conductive additive in LIBs because of its large surface area and terrific electronic conductivity.…”