화학공학소재연구정보센터
Journal of Power Sources, Vol.304, 293-300, 2016
Concentration-gradient LiMn0.8Fe0.2PO4 cathode material for high performance lithium ion battery
It is a great challenge to combine good cycling performance with high rate capability for LiMn1-xMxPO4 cathode materials owing to the Mn dissolution upon cycling and its low electronic/ionic conductivity. Here, we report a novel concentration-gradient structure of LiMn0.8Fe0.2PO4 material constructed by solvothermal treatment. This material shows a linear increase of Mn concentration from the edge to the particle centre, but the inverse trend for Fe concentration, which leads to the formation of Mn-rich phase in bulk and Fe-rich phase at surface. The Fe-rich phase effectively suppresses the corrosion from the electrolyte that minimizes the Mn dissolution and also improves the electronic/ionic conductivity of the surface that decreases the cathode/electrolyte interface resistance. Consequently, this concentration-gradient material achieves superior capacity retention with 98% after 50 cycles at 1 degrees C even at elevated temperature, and also exhibits an excellent rate capability with the reversible capacity of 130 mA h g(-1) at 5 degrees C rate. These results suggest that the concentration-gradient LiMn0.8Fe0.2PO4 is an ideal type of cathode material for high performance Lithium ion batteries. (C) 2015 Elsevier B.V. All rights reserved.