Premium
Combined First‐Principle Calculations and Experimental Study on Multi‐Component Olivine Cathode for Lithium Rechargeable Batteries
Author(s) -
Gwon Hyeokjo,
Seo DongHwa,
Kim SungWook,
Kim Jongsoon,
Kang Kisuk
Publication year - 2009
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200900414
Subject(s) - nanocrystalline material , materials science , electrochemistry , olivine , redox , solid solution , cathode , phase (matter) , lithium (medication) , electrode , analytical chemistry (journal) , mineralogy , chemistry , nanotechnology , metallurgy , medicine , organic chemistry , chromatography , endocrinology
The electrochemical properties and phase stability of the multi‐component olivine compound LiMn 1/3 Fe 1/3 Co 1/3 PO 4 are studied experimentally and with first‐principles calculation. The formation of a solid solution between LiMnPO 4 , LiFePO 4 , and LiCoPO 4 at this composition is confirmed by XRD patterns and the calculated energy. The experimental and first‐principle results indicate that there are three distinct regions in the electrochemical profile at quasi‐open‐circuit potentials of ∼ 3.5 V, ∼4.1 V, and ∼4.7 V, which are attributed to Fe 3+ /Fe 2+ , Mn 3+ /Mn 2+ , and Co 3+ /Co 2+ redox couples, respectively. However, exceptionally large polarization is observed only for the region near 4.1 V of Mn 3+ /Mn 2+ redox couples, implying an intrinsic charge transfer problem. An ex situ XRD study reveals that the reversible one‐phase reaction of Li extraction/insertion mechanism prevails, unexpectedly, for all lithium compositions of Li x Mn 1/3 Fe 1/3 Co 1/3 PO 4 (0 ≤ x ≤ 1) at room temperature. This is the first demonstration that the well‐ordered, non‐nanocrystalline (less than 1% Li–M disorder and a few hundred nanometer size particle) olivine electrode can be operated solely in a one‐phase mode.