Mass production of Li4Ti5O12 with a conductive network via in situ spray pyrolysis as a long cycle life, high rate anode material for lithium ion batteries

Abstract

Nanocrystalline Li₄Ti₅O₁₂ with in situ incorporation of carbon and Ti³⁺ was synthesized by industry scalable in situ spray pyrolysis, producing crystal sizes ranging from 10 to 30 nm. Subsequent annealing in N₂ preserved a proportion of the carbon from the precursor organic salts, predominantly on the Li₄Ti₅O₁₂ grain boundaries, where it formed a conductive network. Such a situation would be expected to inhibit the growth of the primary Li₄Ti₅O₁₂ crystals. The molecular-level uniformity of the precursor allows synthesis of Li₄Ti₅O₁₂ with a significantly shorter heat treatment compared to conventional solid state reaction, which in turn saves energy during large-scale production. Notably, both the nanosized particles and the in situ incorporation of carbon and Ti³⁺ improve the rate capability. In rate capability measurements, stable and high capacity retention was observed from 0.5 C to 30 C. Spray pyrolyzed Li₄Ti₅O₁₂ delivered a discharge capacity of 145.8 mA h g⁻¹ at 10 C for up to 500 cycles. In the full battery tests with Li(Co_0.16Mn_1.84)O₄ as cathode, it also showed excellent capacity and cycling stability, further indicating that spray pyrolyzed Li₄Ti₅O₁₂ is a promising anode material for high power batteries.