Solution-Combustion Synthesized Nanocrystalline Li₄Ti₅O₁₂ As High-Rate Performance Li-Ion Battery Anode

Abstract

Nanocrystalline Li4Ti5O12 (LTO) crystallizing in cubic spinel-phase has been synthesized by single-step-solution-combustion method in less than one minute. LTO particles thus synthesized are flaky and highly porous in nature with a surface area of 12 m2/g. Transmission electron micrographs indicate the primary particles to be agglomerated crystallites of varying size between 20 and 50 nm with a 3-dimensional interconnected porous network. During their galvanostatic charge−discharge at varying rates, LTO electrodes yield a capacity value close to the theoretical value of 175 mA h/g at C/2 rate. The electrodes also exhibit promising capacity retention with little capacity loss over 100 cycles at varying discharge rates together with attractive discharge-rate capabilities yielding capacity values of 140 mA h/g and 70 mA h/g at 10 and 100 C discharge rates, respectively. The ameliorated electrode-performance is ascribed to nano and highly porous morphology of the electrodes that provide short diffusion-paths for Li in conjunction with electrolyte percolation through the electrode pores ensuring a high flux of Li.

Scaling up “Nano” Li4Ti5O12for High-Power Lithium-Ion Anodes Using Large Scale Flame Spray Pyrolysis

“…2 While the enhanced safety and advanced long-term cycling stability, resulting from the relatively higher lithium (de-)insertion potential and the negligible volume variation upon (de-)lithiation, [14][15][16][17] respectively, are, to a great extent intrinsic to LTO, the high power performance, i.e., the rate capability, of the material is highly dependent on the utilized synthesis method and the resulting particle size and morphology. 9,13,[18][19][20][21] Indeed, downsizing the particle size to the nanometer-scale resulted in excellent power performance, [21][22][23][24][25] allowing (dis-)charging LTObased electrodes in as little as a few seconds. However, one of the major challenges toward the commercialization of nano-sized LTO is the development of easily scalable synthesis methods, providing large batches of active material at competitive prices.…”

Role of Metal-Lithium Oxide Interfaces in the Extra Lithium Capacity of Metal Oxide Lithium-Ion Battery Anode Materials

“…SnO + 2Li → Sn + Li 2 O (2 : 1 ratio of Li : Sn) [6] 5Sn + 22Li ↔ Li 22 Sn 5 (4.4 : 1 ratio of Li : Sn) [7] leading to a maximum capacity of 6.4 Li per mole of Sn.…”

“…6 Apart from carbon-based compounds, oxides of titanium that store lithium by means of intercalation have been studied because of their stability, wide availability, low cost, and good reversible capacity at an operating potential of 1.5 V vs Li/Li + . 7 But their theoretical capacity, which is lower than that of graphite (372 mAh g -1 ), and poor electronic conductivity have limited their application in high energy density LiBs. Alloying anode materials such as Si, Sb, Sn, SiO, SnO 2 , and Ge have higher theoretical capacities than graphite, but are limited by high volume expansion and high irreversible capacity losses after first cycle.…”

Li4Ti5O12on Graphene for High Rate Lithium Ion Batteries

“…Spinel Li 4 Ti 5 O 12 (LTO) has a lithium intercalation potential of 1.55 V vs. lithium with a theoretical capacity of 175 mAh g −1 . Due to its high thermal stability, superior safety, and long cycle life, LTO has been considered as a very promising alternative anode material to replace graphite in lithium ion batteries (LIBs), for large-scale storage of electricity, e.g.…”

“…In order to improve the rate performance of LTO, strategies have been developed, mainly aiming at enhancing the electronic and ionic conductivity of LTO. These include: reducing LTO particle size, [4][5][6] coating LTO by conductive carbon, [7][8][9][10] and doping LTO at Li and Ti sites with heteroelements. [11][12][13] Although they could enhance the rate capability of LTO to a certain extend, many obstacles still remain to prevent it from being commercially deployed.…”