KTiOPO4 as a novel anode material for sodium-ion batteries

Highlights: • KTiOPO₄ was prepared through a very simple solid state method. • The mechanism of the compound in the process of sodium ion insertion/extraction includes irreversible phase reaction. • The electrode material shows good electrochemical performance. KTiOPO₄ (KTP) microblocks, which were prepared using a simple solid state method, have been used as novel anode materials for sodium ion batteries (SIBs). The as-prepared KTP microblocks with size distribution of 300–500 nm delivered high performance of electrochemical storage of sodium, such as an initial charge capacity of 108.7 mAh g⁻¹ at 200 mA g⁻¹ with almost no capacity loss in 1000 cycles, and good rate capability of 80.3 mAh g⁻¹ even at the current density of 1000 mA g⁻¹. Ex situ XPS and in situ XRD showed an irreversible phase reaction mechanism during the insertion/extraction of Na⁺. Dendrite formation at lower potential could be suppressed at the average potential of 1.3 V. This work indicated that KTP microblocks are low-cost and safe anode materials for SIBs.