Facile synthesis and lithium reversible insertion on iron hydrated trifluorides FeF3·0.5H2O

International audienceAn original synthesis method for the synthesis of hydrated iron trifluorides is presented for the first time. This method, based on solvothermal process starting from iron salt and HF in alcool, is economic, simple and environmentally benign. The electrochemical performances of the composite phase FeF3·0.5H2O/graphene is showing enhanced capacity of 200 mAh/g at C/20. © 2016 Elsevier B.V. All rights reserved

Facile synthesis and reversible lithium insertion studies on hydrated iron trifluoride FeF3·0.33H2O

International audienceAn original synthesis method for the synthesis of hydrated iron trifluoride is presented. This method, based on solvothermal process starting from iron salt and HF in alcool, is economic and simple. The electrochemical performances of the composite phase FeF3·0.33H2O/Graphitic oxide is showing enhanced capacity of 250 mAh/g at 0.05 °C. © 2016 Elsevier Masson SAS

Solid state studies on K2Ti6-xNbxFe2O16 (x = 0 and 1), and lithium insertion into K2Ti6M2O16 (M = Cr, Fe and Ga) and K2Ti5NbFe2O16 hollandite type phases

A new niobium-substituted hollandite K2Ti5NbFe2O16 has been synthesised for the first time. The compound is crystallised in tetragonal structure. A two to three orders change in electrical resistivity is observed with temperature as compared to the parent phase K2Ti6Fe2O16. The niobium-substituted phase shows antiferromagnetic ordering with TN=37 K at a field of 0.1 T and the antiferromagnetic ordering disappears at higher field (0.2 T) indicating field induced magnetic behaviour. The Mössbauer spectrum of K2Ti5NbFe2O16 shows majority of the Fe ions are 3+ oxidation state (96%). For the first time, we have intercalated lithium into K2Ti6M2O16 (M=Cr, Fe and Ga) and K2Ti5NbFe2O16 hollandite type phases using n-butyllithium in hexane. The estimated lithium content for all the phases are in the range 1.7–2.7 mol per formula unit

Facile synthesis and reversible lithium insertion studies on hydrated iron trifluoride FeF3·0.33H2O

An original synthesis method for the synthesis of hydrated iron trifluoride is presented. This method, based on solvothermal process starting from iron salt and HF in alcool, is economic and simple. The electrochemical performances of the composite phase FeF3·0.33H2O/Graphitic oxide is showing enhanced capacity of 250 mAh/g at 0.05 °C. © 2016 Elsevier Masson SAS

Facile synthesis and lithium reversible insertion on iron hydrated trifluorides FeF3·0.5H2O

An original synthesis method for the synthesis of hydrated iron trifluorides is presented for the first time. This method, based on solvothermal process starting from iron salt and HF in alcool, is economic, simple and environmentally benign. The electrochemical performances of the composite phase FeF3·0.5H2O/graphene is showing enhanced capacity of 200 mAh/g at C/20. © 2016 Elsevier B.V. All rights reserved

Monoclinic iron hydroxy sulphate: A new route to electrode materials

The monoclinic form of FeOHSO4 was prepared by dehydration of FeSO4·7H2O. We show that reversible insertion of up to ∼1Li/f.u. is possible in this compound at an average voltage of 3.2 V. The insertion/deinsertion is a biphasic process. The high voltage plateau, a reversible capacity of 110 mAh/g after 20 cycles and good cycling behavior make this compound an attractive positive electrode material for rechargeable Li-ion batteries, suggesting also that transition metal sulphates need to be explored. Keywords: Iron hydroxy sulphate, Li-ion batteries, Cathode, Lithium insertio

Pb 3O 4 type antimony oxides MSb 2O 4 (M = Co, Ni) as anode for Li-ion batteries

10.1016/j.electacta.2012.03.145Electrochimica Acta71227-232ELCA

A new wide band gap thermoelectric quaternary selenide Cu2MgSnSe4

International audienceCu2MgSnSe4 based compounds composed of high earth abundant elements have been identified to exhibit good thermoelectric performance in the mid-temperature range. The pristine phase shows a band gap of 1.7 eV, which is slightly higher than similar ternary and quaternary copper based stannite compounds. Cu2MgSnSe4 crystallizes in the tetragonal I4¯2m space group. Substitution of In at Sn site tends to decrease the tetragonal distortion toward the cubic symmetry. The electrical and thermal transport properties of Cu and In-doped Cu2MgSnSe4 in the temperature range of 300 K-700 K are studied. The substitution of In3+ for Sn4+ and Cu2+ for Mg2+ induces charge carriers as holes, which in turn lead to improvement in thermoelectric efficiency. The role of mass fluctuations and structural disorder in the evolution of the thermal conductivity of the doped selenides is discussed. A maximum ZT of 0.42 is attained for Cu2MgSn0.925In0.075Se4 around 700 K, and this value is comparable to that of Cu2ZnSnSe4. © 2015 AIP Publishing LLC