Lithium Titanate Tailored by Cathodically Induced Graphene for an Ultrafast Lithium Ion Battery

Abstract

Lithium titanium oxide with the cubic spinel structure, Li 4 Ti 5 O 12 (LTO), has been extensively investigated as anode materials for the next-generation lithium ion batteries because of its intrinsic characteristics, such as the stable charge/discharge platform at 1.5 V vs. Li + /Li, which is just above the formation of SEI. Also note that it has zero strain features during the lithium intercalation/extraction. [9][10][11][12][13][14] It was not surprising to see that proprietary nanostructured LTO was fi rstly introduced to replace the traditional graphite materials in EVs and advanced energy storage systems by Altairnano. [ 15 ] Nevertheless, the rate performance of pristine LTO is relatively poor due to its moderate Li + diffusion coeffi cient and low electrical conductivity. It should be pointed out that the LTO-based LIBs suffer from severe gassing during charge/discharge cycles, resulting from interfacial reactions between LTO and surrounding alkyl carbonate solvents, which hinders its large-scale applications in LIBs industries. [16][17][18][19] To suppress the gassing issues, an effective strategy of constructing a barrier between the LTO and the surrounding electrolyte solution has been designed. [ 19 ] In terms of the improvement of rate capability, many methods including designing of novel micro-nanostructure, doping with foreign atoms and conductive agents incorporating, have been exploited up to now. [ 10,13,14 ] Micro-nanostructured LTO materials, with short transportation distance for both Li + and electrons, have been extensively developed to increase the rate capability. [20][21][22][23][24] However, the preparation of these structured materials in large scale is costly and quite challenging. The conductivity and rate performance of LTO can also be tuned by doping some foreign atoms. [ 10,13,14,25,26 ] Recently, phosphidated-Li 4 Ti 5 O 12 was fabricated by Park et al. via the thermal decomposition of trioctylphosphine. [ 24 ] This material with enhanced Li + conductivity improved the rate performance to a capacity of 100 mAh g −1 at a rate of 10C (1C = 175 mA g −1 ). This enhancement is meaningful but still not good enough for applications in EVs or large-scale energy storage.Another good choice to enhance the rate performance is conductive agents incorporating. Graphene, a single-atomthick sheet of honeycomb carbon lattice, was recently chosen as a conductive additive to improve the capabilities of LTO composites due to its superior electrical conductivity (64 mS cm −1 ), extremely high theoretical surface area (2675 m 2 g −1 ) andNonoxidative cathodically induced graphene (CIG) here incorporates conductive agents for Li 4 Ti 5 O 12 (LTO) anode materials. The tailored LTO/CIG composite is fabricated by controlled hydrolysis of tetrabutyl titanate in the presence of nonoxidative defect-free cathodically induced graphene (CIG) and oxalic acid in a mixed solvent of ethanol and water, followed by hydrothermal reaction and a calcination treatment. Due to the introduction of defect-free graphene, t...

Critical Insight into the Relentless Progression Toward Graphene and Graphene‐Containing Materials for Lithium‐Ion Battery Anodes

“…It should be noticed that few papers [ 271,276,[401][402][403][404] have reported the evaluation of the energy and power for a single electrode in half-cell confi guration. As previously explained in Section 3.2 , we want to stress that this kind of calculation is not appropriate to assess the properties of electroactive materials, since no coupling with a cathode material was neither performed nor simulated.…”

The Improvement of Discharge Capacity of Zr-doped Lithium Titanate for Lithium Ion Batteries

“…It has a pair of long and stable charge and discharge potential flats, and the discharge potential is about 1.55 V (vs Li/Li + ), which is above the reduction potential of common electrolyte so that can hinder the formation of solid electrolyte interface (SEI). And this high potential also avoids the lithium dendrite deposition on the surface of the anode material [3,4]. In addition, LTO is an ideal "zero strain" material because of no change of its lattice parameters and volume during lithium ion insertion/extraction processes.…”

“…[1,2] Spinel lithium titanate (Li 4 Ti 5 O 12 , LTO) is one of important anode materials of LIBs. It has a pair of long and stable charge and discharge potential flats, and the discharge potential is about 1.55 V (vs Li/Li + ), which is above the reduction potential of common electrolyte so that can hinder the formation of solid electrolyte interface (SEI).…”

One-step, continuous synthesis of a spherical Li4Ti5O12/graphene composite as an ultra-long cycle life lithium-ion battery anode

“…22,[40][41][42][43] The typical performance of LTO/RGO anodes from this method includes 144 mAh g − 1 at 10C (retained 85% after 2000 cycles) 40 and 162 mAh g − 1 at 10C (retained 90.7% after 500 cycles). 43 Another method for preparing LTO/RGO composite, as reported by Oh et al 44 is wrapping GO sheets onto a TiO 2 (P25) particle, followed by annealing in the presence of Li 2 CO 3 . LTO/RGO composites prepared with this method also exhibited good rate capability, for example, delivering~105 mAh g − 1 at 100C.…”