Journal of Power Sources, Vol.259, 177-182, 2014
Copper/carbon coated lithium sodium titanate as advanced anode material for lithium-ion batteries
Core shell Li2Na2Ti6O14@Cu/C is prepared by a preliminary formation of Li2Na2Ti6O14 by solid state reaction and a following coating process with Cu/C layer by thermal decomposition. The amorphous Cu/C coating layer reveals a thickness of 5 nm on the surface of Li2Na2Ti6O14, which improves the electronic conductivity and charge transfer rate of active materials. As a result, Li2Na2Ti6O14@Cu/C shows lower electrochemical polarization and quicker kinetic behavior compared to bare Li2Na2Ti6O14. Cycled at 50 mA g(-1), Li2Na2Ti6O14@Cu/C can deliver a reversible capacity of 120.3 mAh g(-1) after 50 cycles, which is much higher than the value of 96.8 mAh g(-1) obtained by Li2Na2Ti6O14. Even kept at 400 mA g(-1), a reversible lithium storage capacity of 76.3 mAh g(-1) can be delivered by Li2Na2Ti6O14@Cu/C. The improved electrochemical properties of Li2Na2Ti6O14 are attributed to the electronic conductive Cu/C coating layer on the surface. (C) 2014 Elsevier B.V. All rights reserved.