CPM Seminar

Safe Li-ion Batteries for Green Transportation and Energy Storage

Karim Zaghib

Institut de Recherche d'Hydro Québec, Varennes

Besides the market for portable electronic devices, the Li-ion technology is starting to penetrate other markets such as hybrid electric vehicles (HEV) and plug-in HEV (PHEV) [1-4]. However, there are many features that must be solved before the use of Li-ion batteries in HEVs, including low cost, long calendar life, safety, and high power capability [5-6]. Safety is one of the crucial issues for advanced applications of Li-ion batteries. So far, LiCoO₂ has been the favorite cathode material used in Li-ion batteries, owing to its high energy density. However, the questionable long-term supply of cobalt material and its high cost present an uncertain future, while an alternative cathode material, that is Co-free, is urgently needed to prepare for the future applications of Li-ion battery technology in HEVs and PHEVs. Since the demonstration of LiFePO₄ by Padhi et al. [7], as a potential cathode material, considerable interest has been generated due to its safety, low cost and environment friendly nature. Furthermore, side reactions are minimized because of its flat voltage profile at 3.4 Volts vs. Li⁰/Li⁺.

In this work, we have selected various positive electrode materials with either the orthophosphate (olivine-like) or orthosilicate frameworks; they are evaluated with lithium graphite and LTO as anodes materials. LiMPO₄ (with M= Fe, Mn, Co) cathodes are evaluated in lithium cells using ionic liquids. Such cells are compared to the conventional ones using electrolytes with LiPF₆ or LiFSI salt. The electrochemical investigations include interface impedance, rate performance and cyclability.

[1] T. Tanaka, K. Ohta, N. Arai, J. Power Sources 97-98 (2001) 2.
[2] R.A. March, S. Vukson, S. Sarampudi, B.V. Ratnakumar, M.C. Smart, M. Manzo, P.J. Dalton, J. Power Sources 97-98 (2001) 236.
[3] T. Takamura, Solid State Ionics 152-153 (2002) 19.
[4] K. Zaghib, P. Charest, A. Guerfi, J. Shim, M. Perrier, K. Striebel, J. Power Sources 134 (2004) 124.
[5] PNGV FreedomCar manual, T.Q. Duong, J. Power Sources 89 (2000) 244.
[6] N. Terada, T. Yanagi, S. Arai, M. Yoshikawa, K. Ohta, N. Nakajima, N. Arai, J. Power Sources 100 (2001) 80.
[7] A.K. Padhi, K.S. Nanjundaswany, J.B. Goodenough, J. Electrochem. Soc. 144 (1997) 1188.