Electronically conductive phospho-olivines as lithium storage electrodes.
Lithium transition metal phosphates have become of great interest as storage cathodes for rechargeable lithium batteries because of their high energy density, low raw materials cost, environmental friendliness and safety. Their key limitation has been extremely low electronic conductivity, until now believed to be intrinsic to this family of compounds. Here we show that controlled cation non-stoichiometry combined with solid-solution doping by metals supervalent to Li+ increases the electronic conductivity of LiFePO4 by a factor of approximately 10(8). The resulting materials show near-theoretical energy density at low charge/discharge rates, and retain significant capacity with little polarization at rates as high as 6,000 mA x g(-1). In a conventional cell design, they may allow development of lithium batteries with the highest power density yet.
Chung
Sung-Yoon
SY
Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
Bloking
Jason T
JT
Chiang
Yet-Ming
YM
D025802:Electric Capacitance; D004553:Electric Conductivity; D011211:Electric Power Supplies; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D007501:Iron / Q000737:chemistry*; D058085:Iron Compounds / Q000737:chemistry; D008094:Lithium / Q000737:chemistry*; D017616:Magnesium Compounds / Q000737:chemistry; D008422:Materials Testing / Q000379:methods*; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D010710:Phosphates / Q000737:chemistry*; D012680:Sensitivity and Specificity; D017640:Silicates / Q000737:chemistry
D058085:Iron Compounds; C473349:LiFePO4; D017616:Magnesium Compounds; D008670:Metals; D010710:Phosphates; D017640:Silicates; C034475:olivine; D008094:Lithium; D007501:Iron