A Carbothermal Reduction Method for the Preparation of Electroactive Materials for Lithium Ion Applications

Abstract

A novel preparative method based on a carbothermal reduction ͑CTR͒ process is described for the synthesis of the representative electroactive materials, ␥-LiV 2 O 5 and Li 3 V 2 (PO 4 ) 3 . In the CTR procedure a high surface area carbon is mixed intimately with appropriate precursor compounds and the mixture heated in an inert atmosphere. Use is then made of the two carbon oxidation reactions, namely, C → CO 2 and C → CO which facilitate controlled transition metal reduction while also allowing lithium ion incorporation. Electrochemical performance evaluation indicates that the CTR ␥-LiV 2 O 5 is capable of cycling at a material utilization of 130 mAh/g, a figure that compares favorably with the theoretical specific capacity of 142 mAh/g. The insertion behavior of the lithium vanadium phosphate shows a specific capacity equivalent to the reversible cycling of two lithium ions per Li 3 V 2 (PO 4 ) 3 formula unit. In summary, we believe the CTR method to be an energy-efficient, economical, and convenient process to produce a wide range of electroactive compounds. It appears ideally suited to preparation of active materials for use in lithium ion applications.

Optimization of carbon coatings on LiFePO4

“…LiFePO 4 may be prepared by a number of different routes, including hydrothermal synthesis [12,13], carbothermal reduction [14], sol-gel [9,15,16,17] or aqueous precipitation routes [18], microwave processing [19], and solid-state synthesis under an inert or reducing atmosphere [20,21]. Samples made from precursors with organic moieties (oxalates, acetates, etc.)…”

High‐Rate LiFePO4 Electrode Material Synthesized by a Novel Route from FePO4 · 4H2O

“…[9] Another obstacle to the commercial application of LiFePO 4 lies in the large-scale synthesis techniques. In recent years, various synthesis routes were proposed to prepare LiFePO 4 , such as mechanical alloying, [10,11] sol-gel methods, [12,13] co-precipitation, [14] microwave processes, [15] hydrothermal routes, [16,17] emulsion drying synthesis, [18,19] a carbothermal reduction method, [20] vapor deposition, [21] spray solution technology, [22] and so forth. The most common and traditional method to manufacture LiFePO 4 is still solid-state reaction synthesis, which entails several grinding and long-time calcining cycles.…”

Influence of Adipic Acid on Electrochemical Properties of Li3V2 (PO4)3 as Cathode Material for Rechargeable Lithium-Ion Batteries

“…Lithium transition metal phosphates, such as LiFePO 4 [3], LiCoPO 4 [4], LiMnPO 4 [5], LiNiPO 4 [6], Li 3 Ti 2 (PO 4 ) 3 [7] and Li 3 V 2 (PO 4 ) 3 [8][9][10][11][12][13][14] have been focus of candidate as cathode materials. Among the phosphates above, monoclinic Li 3 V 2 (PO 4 ) 3 is a highly promising material proposed as a cathode for higher voltage rechargeable lithium-ion batteries because of their stable framework, good ion mobility and high reversible capacity.…”

“…Among the optimized conditions, the sample prepared with 0.15 molar ratio of adipic acid to total metal ions at the calcination temperature of 900 0 C showed a better electrochemical performance compared to other samples. [8][9][10][11][12][13][14] have been focus of candidate as cathode materials. Among the phosphates above, monoclinic Li 3 V 2 (PO 4 ) 3 is a highly promising material proposed as a cathode for higher voltage rechargeable lithium-ion batteries because of their stable framework, good ion mobility and high reversible capacity.…”