Chemically driven synthesis of Ti³⁺ self‐doped Li₄Ti₅O₁₂ spinel in molten salt

Abstract

Surface doping of Li 4 Ti 5 O 12 (LTO) with Ti 3+ ions is an effective way to enhance its electrochemical properties for lithium ion batteries (LIBs). Herein, a molten salt approach was reported to synthesize Ti 3+ self-doped LTO powder. The reaction mechanism and the role of molten salt for the synthesis have been systemically discussed. Finally, electrochemical performance of the LTO powder was preliminarily evaluated as anode material of LIBs. The molten salt accelerated the mass transportation for the formation of LTO by transferring a solid diffusion to the diffusion of ions in a liquid media. Self-doping of Ti 3+ ions on the surface of LTO particles was achieved by controlling equilibriums of chemical reactions in the reactor. Electrochemical performance of the LTO powders was effectively promoted by doping Ti 3+ ions on the surface. The discharge capacity of the Ti 3+ self-doped LTO powder prepared at 850°C was 171 mAhg −1 , and the capacity dacayed 9.9% after 200 cycles at a rate of 0.5 C. K E Y W O R D S kinetics, Li 4 Ti 5 O 12 , Li-ion batteries, molten salt, Ti 3+ doping 754 | XIE Et al.

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

“…Additionally, the high-temperature post-treatment is not desirable in terms of fabrication expenses. Conventional synthesis techniques include solid-state reaction (SSR) [ 25 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ], hydrothermal [ 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 ], solvothermal method [ 59 , 60 ], sol–gel method [ 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 ], biphasic interfacial reaction [ 71 ], spray pyrolysis [ 72 , 73 , 74 , 75 , 76 , 77 , 78 ], molten-salt method [ 79 , 80 , 81 , 82 ], microwave heating method [ 83 , 84 ], template method [ 85 , 86 , 87 , 88 , 89 ], emulsion-gel process [ 90 …”

High Performance Ti3+ Self-Doped Li4Ti5O12 Anode Materials Synthesized by an Electrochemical Method in Molten Salt

“…), or the doped by ions (Al 3+ , Mn 2+ , Cu 2+ , Zn 2+ , Cr 3+ , V 5+ , Ni 2+ , Cd 2+ , Ge 4+ , etc. ), [14][15][16][17][18][19][20][21][22] or the self-doping Ti 3+ ion 23 are also employed to further improve its rate performance. Liu et al prepared Li 4 Ti 5 O 12 nanocrystals of 30 ∼ 50 nm size with specific surface area of 46.3 m 2 •g −1 and high capacity of 136 mAh•g −1 at 5 C, using the organic Ti(OC 3 H 7 ) 4 aqueous, LiOH aqueous, and the n-pentanol/ cetyltrimethylammonium bromide/cyclohexane mixtures to precipitate for 24 h and anneal.…”

“…30 Xie et al synthesized the Ti 3+ self-doped Li 4 Ti 5 O 12 spinel with micrometer-sized by chemically driven synthesis in molten LiCl-KCl using 200 nm TiO 2 size and Li 2 CO 3 as raw materials. 23 However, the size of these Ti 3+ selfdoped Li 4 Ti 5 O 12 significantly depended on the size of the raw material particles, especially size of the TiO 2 , which resulted in their large size and limited the further improvement of conductivity. Therefore, it is necessary to design a simple synthesis method of Li 4 Ti 5 O 12 with uniform small size and Ti 3+ self-doped.…”