Details

Autor(en) / Beteiligte

• Zhang, Zhongyu
• Li, Malin
• Gao, Yu
• Wei, Zhixuan
• Zhang, Meina
• Wang, Chunzhong
• Zeng, Yi
• Zou, Bo
• Chen, Gang
• Du, Fei

Titel

Fast Potassium Storage in Hierarchical Ca0.5Ti2(PO4)3@C Microspheres Enabling High‐Performance Potassium‐Ion Capacitors

Ist Teil von

• Advanced functional materials, 2018-09, Vol.28 (36), p.n/a

Ort / Verlag

Hoboken: Wiley Subscription Services, Inc

Erscheinungsjahr

2018

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Hybrid potassium‐ion capacitors (KICs) show great promise for large‐scale storage on the power grid because of cost advantages, the weaker Lewis acidity of K+ and low redox potential of K+/K. However, a huge challenge remains for designing high‐performance K+ storage materials since K+ ions are heavier and larger than Li+ and Na+. Herein, the synthesis of hierarchical Ca0.5Ti2(PO4)3@C microspheres by use of the electrospraying method is reported. Benefiting from the rich vacancies in the crystal structure and rational nanostructural design, the hybrid Ca0.5Ti2(PO4)3@C electrode delivers a high reversible capacity (239 mA h g−1) and superior rate performance (63 mA h g−1 at 5 A g−1). Moreover, the KIC employing a Ca0.5Ti2(PO4)3@C anode and activated carbon cathode, affords a high energy/power density (80 W h kg−1 and 5144 W kg−1) in a potential window of 1.0–4.0 V, as well as a long lifespan of over 4000 cycles. In addition, in situ X‐ray diffraction is used to unravel the structural transition in Ca0.5Ti2(PO4)3, suggesting a two‐phase transition above 0.5 V during the initial discharge and solid solution processes during the subsequent K+ insertion/extraction. The present study demonstrates a low‐cost potassium‐based energy storage device with high energy/power densities and a long lifespan. A hybrid potassium‐ion capacitor using hierarchical Ca0.5Ti2(PO4)3@C microspheres as anode and activated carbon as cathode is shown. The potassium‐ion storage device delivers a high power density of 5144 W kg−1 at an energy density of 34 W h Kg−1 with a long lifespan of 4000 cycles in the potential range of 1.0–4.0 V.