Abstract
Severe structural evolution and high content of [Fe(CN)6]4- defects drastically deteriorate K-ion storage performances of Prussian blue-based cathodes. Herein, a potassium manganese iron copper hexacyanoferrate (KFe2/3Mn1/6Cu1/6HCF), with suppressed anionic vacancies, eliminated band gap, and low K-ion diffusion barrier, is regarded as a cathode for potassium-ion batteries. The entropy stabilization effect and robust Cu-N bond induced by the inert Cu-ion with large electronegativity boost KFe2/3Mn1/6Cu1/6HCF to exhibit great phase state stability, thus inhibiting the structural transition of monoclinic ↔ cubic. Hence, KFe2/3Mn1/6Cu1/6HCF undergoes a zero-stress solid-solution reaction mechanism, where Fe and Mn serve as dual active sites for charge compensation. Consequently, KFe2/3Mn1/6Cu1/6HCF displays a high reversible capacity of 127.5 mAh·g-1 with an energy density of 469.2 Wh·kg-1 at 10 mA·g-1 and superior cyclic stability with a high retention of 90.7% over 100 cycles. A high-energy-density K-ion full battery is assembled, contributing an ultralong lifetime over 1000 cycles with a low-capacity fading rate of 0.038% per cycle.
Original language | English |
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Pages (from-to) | 15167-15177 |
Number of pages | 11 |
Journal | Nano Letters |
Volume | 24 |
Issue number | 47 |
DOIs | |
State | Published - 27 Nov 2024 |
Keywords
- Cathode materials
- Phase transition mechanism, Entropy
- Potassium-ion batteries
- Prussian blue