A short review on the comparison between Li battery systems and rechargeable magnesium battery technology

An active metal that should be considered as an anode material in high ener gy density batteries is definitely magnesium. It is relatively cheap, much safer to use and handle than lithium, and its compounds are usually non-tox ic. Similar to lithium, magnesium is covered by surface films in any 'inert' at mosphere that contains atmospheric contaminants, and in most of the relevan t electrolyte solutions for batteries. In contrast to lithium where the sur face films covering the active metal are Li-ion conductors, surface films f ormed similarly an magnesium cannot conduct the bivalent Mg2+ ions. We deve loped new electrolyte solutions based on ethers of the 'glyme' family and m agnesium aluminates whose electrochemical window is 2.5 V wide. The efficie ncy of Mg deposition-dissolution cycles in these solutions is higher than 9 9%. We also showed that it is possible to construct rechargeable Mg batteri es using these electrolyte solutions and cathodes of the MgxMoSy type (chev rel phase), which operate at 1-1.5 V, and can deliver more than 1000 charge -discharge cycles. Some technical details of these battery systems are disc ussed. (C) 2001 Elsevier Science B.V. All rights reserved.