Use of a novel layered titanoniobate as an anode material for long cycle life sodium ion batteries

Sodium ion batteries have been attracting increasing attention as a replacement for lithium ion batteries in large-scale energy applications. However, it is proving difficult to find suitable sodium host materials with both a high capacity and excellent cycle stability. We prepared a layered titanoniobate (HTi₂NbO₇) via solid-state calcination followed by ion exchange for use in sodium ion batteries. The lamellar HTi₂NbO₇ had a specific capacity of about 90 mA h g^-1 at 100 mA g^-1. The capacity was highly reversible over 2000 cycles. These results show that this lamellar titanoniobate material is a promising anode material for sodium ion batteries with a long cycle life.