TY - JOUR
T1 - KTi2(PO4)3 Electrode with a Long Cycling Stability for Potassium-Ion Batteries
AU - Voronina, Natalia
AU - Jo, Jae Hyeon
AU - Konarov, Aishuak
AU - Kim, Jongsoon
AU - Myung, Seung Taek
N1 - Funding Information:
This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science, and Technology of Korea (NRF 2015M3D1A1069713, NRF 2017R1E1A2A01079404, NRF 2017M2A2A6A01070834, and NRF 2017K1A3A1A30084795).
Publisher Copyright:
© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2020/1/1
Y1 - 2020/1/1
N2 - In this work, rhombohedral KTi2(PO4)3 is introduced to investigate the related theoretical, structural, and electrochemical properties in K cells. The suggested KTi2(PO4)3 modified by electro-conducting carbon brings about a flat voltage profile at ≈1.6 V, providing a large capacity of 126 mAh (g-phosphate)−1, corresponding to 98.5% of the theoretical capacity, with 89% capacity retention for 500 cycles. Structural analyses using electrochemical performance measurements, first-principles calculations, ex situ X-ray absorption spectroscopy, and operando X-ray diffraction provide new insights into the reaction mechanism controlling the (de)intercalation of potassium ions into the host KTi2(PO4)3 structure. It is observed that a biphasic redox process by Ti4+/3+ occurs upon discharge, whereas a single-phase reaction followed by a biphasic process occurs upon charge. Along with the structural refinement of the electrochemically reduced K3Ti2(PO4)3 phase, these new findings provide insight into the reaction mechanism in Na superionic conductor (NASICON)-type KTi2(PO4)3. The present approach can also be extended to the investigation of other NASICON-type materials for potassium-ion batteries.
AB - In this work, rhombohedral KTi2(PO4)3 is introduced to investigate the related theoretical, structural, and electrochemical properties in K cells. The suggested KTi2(PO4)3 modified by electro-conducting carbon brings about a flat voltage profile at ≈1.6 V, providing a large capacity of 126 mAh (g-phosphate)−1, corresponding to 98.5% of the theoretical capacity, with 89% capacity retention for 500 cycles. Structural analyses using electrochemical performance measurements, first-principles calculations, ex situ X-ray absorption spectroscopy, and operando X-ray diffraction provide new insights into the reaction mechanism controlling the (de)intercalation of potassium ions into the host KTi2(PO4)3 structure. It is observed that a biphasic redox process by Ti4+/3+ occurs upon discharge, whereas a single-phase reaction followed by a biphasic process occurs upon charge. Along with the structural refinement of the electrochemically reduced K3Ti2(PO4)3 phase, these new findings provide insight into the reaction mechanism in Na superionic conductor (NASICON)-type KTi2(PO4)3. The present approach can also be extended to the investigation of other NASICON-type materials for potassium-ion batteries.
KW - first-principles calculations
KW - insertion
KW - KTi(PO)
KW - potassium-ion batteries
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U2 - 10.1002/smll.202001090
DO - 10.1002/smll.202001090
M3 - Article
AN - SCOPUS:85083768027
SN - 1613-6810
VL - 16
JO - Small
JF - Small
IS - 20
M1 - 2001090
ER -