KTiOPO4: A long-life, high-rate and low-temperature-workable host for Na/K-ion batteries

Discovering high-performance electrode materials for Na/K-ion batteries (NIBs/KIBs) is crucially important for the development of low-cost energy storage systems. Herein, a kind of well-crystallized KTiOPO4 nanoparticles is reported as a long-life, high-rate and low-temperature-workable host for Na/K ions batteries. Without any carbon coating and high-temperature treatment, the resulting KTiOPO4 nanoparticles exhibit impressive electrochemical performance in Na/K-ion batteries, in terms of high reversible capacities, superior rate capabilities (103.0 mA h g(-1) at 100C in NIBs and 83.6 mA h g(-1) at 20C in KIBs) and outstanding cycling stability (91% capacity retention at 30C in NIBs after 1000 cycles and 78.4% capacity retention at 20C in KIBs after 10,000 cycles). Extraordinarily, it can be cycled well at low temperatures (no capacity decay after 550 cycles at 3C and -35 degrees C) and in Na-ion full cells. Besides, it is demonstrated that the outstanding electrochemical performance could be attributed to the stable framework and highly reversible reactions during the Na+/K+ (de)insertion process. These findings prove that the as-reported KTiOPO4 product is a promising candidate as Na/K-ion reservoirs.

Automated summary

The well-crystallized KTiOPO4 nanoparticles reported in this study demonstrate impressive electrochemical performance in Na/K-ion batteries, with high reversible capacities, superior rate capabilities, and outstanding cycling stability. The outstanding performance is attributed to the stable framework and highly reversible reactions during the Na+/K+ (de)insertion process, making the KTiOPO4 nanoparticles a promising candidate as Na/K-ion reservoirs.