Novel sodium/lithium-ion anode material based on ultrathin Na₂Ti₂O₄(OH)₂ nanosheet

Ultrathin Na₂Ti₂O₄(OH)₂ nanosheets of ∼8 nm thickness were prepared by a facile method for the first time. The resulting material was also used as a conducting agent and binder-free anode, both for sodium-ion batteries and lithium-ion batteries, for the first time. The Na₂Ti₂O₄(OH)₂ nanosheets exhibited excellent Na/Li-ion storage performance. A long-term cycling performance of the ultrathin Na₂Ti₂O₄(OH)₂ nanosheets of 120 mA h g^-1 at ∼10C was retained after 500 cycles for sodium-ion batteries, and 150 mA h g^-1 at ∼1C was kept after 500 cycles for lithium-ion batteries. By comparison, the Na-ion storage performance is much better than the Li-ion storage performance of the Na₂Ti₂O₄(OH)₂ nanosheets anode, because of the existence of Na in the Na₂Ti₂O₄(OH)₂ host.