Structurally stabilized olivine lithium phosphate cathodes with enhanced electrochemical properties through Fe doping

Authors

Yong-Mook Kang, Kongju National University
Y Kim
Min-Wook Oh, Korea Electrotechnology Research Institute, Korea
Ri-Zhu Yin, Yonsei University, Seoul, Republic of Korea
Youngmin Lee, Kongju National University, Republic of Korea
Dong-Wook Han, Korea Advanced Institute of Science Technology
Hyuk-Sang Kwon, korea advanced Institute of Science Technology
Jung Ho Kim, University of WollongongFollow
Ganpati Ramanath, Rensselaer Polytechnic Institute

RIS ID

44501

Publication Details

Kang, Y., Kim, Y., Oh, M., Yin, R., Lee, Y., Han, D., Kwon, H., Kim, J. Ramanath, G. (2011). Structurally stabilized olivine lithium phosphate cathodes with enhanced electrochemical properties through Fe doping. Energy and Environmental Science, 4 (12), 4978-4983.

Abstract

Controlling the crystallographic structure in olivine lithium phosphates is crucial for obtaining superior electronic (J. Electrochem. Soc., 2002, 149, A1184-A1189) and ionic conductivities (Electrochem. Solid-State Lett., 2006, 9, A352-A355; Electrochem. Solid-State Lett., 2006, 9, A439-A442; Nat. Mater., 2002, 1, 123-128), and stability, for use as cathodes in lithium batteries. Here, we report a completely new approach to enhance Li⁺ extraction and transport in LiCoPO₄ through Fe doping. We show that preferential Fe occupation of the 4c sites suppresses 4a–4c antisite mixing of Li and Co, thereby stabilizing the olivine structure by compensating for the Co-encapsulating oxygen octahedron shrinkage due to Co²⁺ oxidation during Li⁺ extraction. The structural stabilization gives rise to 10% higher charge capacity at a two-fold lower resistance than the undoped counterparts besides accelerating the intercalation/extraction kinetics. Our findings provide key atomistic-level insights that pave the way for the rational design and realization of new types of metal-doped cathode materials for lithium batteries and related applications.