Copper/carbon coated lithium sodium titanate as advanced anode material for lithium-ion batteries

Core–shell Li 2 Na 2 Ti 6 O 14 @Cu/C is prepared by a preliminary formation of Li 2 Na 2 Ti 6 O 14 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 Li 2 Na 2 Ti 6 O 14 , which improves the electronic conductivity and charge transfer rate of active materials. As a result, Li 2 Na 2 Ti 6 O 14 @Cu/C shows lower electrochemical polarization and quicker kinetic behavior compared to bare Li 2 Na 2 Ti 6 O 14 . Cycled at 50 mA g −1 , Li 2 Na 2 Ti 6 O 14 @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 Li 2 Na 2 Ti 6 O 14 . Even kept at 400 mA g −1 , a reversible lithium storage capacity of 76.3 mAh g −1 can be delivered by Li 2 Na 2 Ti 6 O 14 @Cu/C. The improved electrochemical properties of Li 2 Na 2 Ti 6 O 14 are attributed to the electronic conductive Cu/C coating layer on the surface.