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
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 Li4Ti 5O12 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 Li4Ti 5O12 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(Co0.16Mn 1.84)O4 as cathode, it also showed excellent capacity and cycling stability, further indicating that spray pyrolyzed Li4Ti 5O12 is a promising anode material for high power batteries.