Carbon Coated Electrochemically Active Powder

Abstract

The invention relates to an electrochemically active powder comprising particles containing a compound represented by formula A a M m (XO 4 ) n wherein A comprises an alkaline metal; M comprises at least one transition metal and optionally at least one non-transition metal; and X is chosen among S, P and Si; wherein 0<a≦3.2; 1≦m≦2; and 1≦n≦3; wherein said particles are at least partially coated with a layer comprising a carbonaceous material, said carbonaceous material comprising a highly ordered graphite, wherein said highly ordered graphite has a ratio (I 1360 /I 1580 ) of a peak intensity (I 1360 ) at 1360 cm −1 to a peak intensity (I 1360 ) at I 1580 cm −1 , obtained by Raman spectrum analysis, of at most 3.05.

1 - 17 . (canceled) 
     
     
         18 . An electrochemically active powder comprising particles which contain a core which is provided with a coating layer, whereby the core contains a compound represented by formula Li a M m (XO 4 ) n  wherein M comprises at least one transition metal and optionally at least one non-transition metal; and X is selected from the group consisting of S, P and Si; wherein 0<a≦3.2; 1≦m≦2; and 1≦n≦3; wherein said particles are at least partially coated by said coating layer and whereby the coating layer comprises a carbonaceous material, said carbonaceous material comprising a highly ordered graphite, wherein said highly ordered graphite has a ratio (I 1360 /I 1580 ) of a peak intensity (I 1360 ) at 1360 cm −1  to a peak intensity (I 1580 ) at 1580 cm −1 , obtained by Raman spectrum analysis, of at least 1.5 and at most 3.05. 
     
     
         19 . The powder of  claim 18 , wherein X is P. 
     
     
         20 . The powder of  claim 18 , wherein M comprises a transition metal comprising iron, manganese, vanadium, titanium, molybdenum, niobium, tungsten, zinc and mixtures thereof. 
     
     
         21 . The powder of  claim 18 , wherein the compound is characterized by the formula LiMPO 4 , and where M comprises a metallic cation belonging to the first line of transition metals. 
     
     
         22 . The powder of  claim 18 , wherein the compound is characterized by the formula Li a M 1-y M′ y (XO 4 ) n , in which 0≦a≦2; 0≦y≦0.6 and 1≦n≦1.5, wherein M comprises a transition metal or a mixture of transition metals from the first line of the periodic table; M′ comprises an element with fixed valence selected from the group consisting of Mg 2+ , Ca 2+ , Al 3+ , Zn 2+  and a combination of these same elements. 
     
     
         23 . The powder of  claim 18 , wherein the compound is characterized by the formula Li a (M,M′)PO 4 , wherein 0≦a≦1, M comprises one or more cations selected from the group consisting of Mn, Fe, Co, Ni, and Cu, and M′ comprises an optional substitutional cation selected from the group consisting of Na, Mg, Ca, Ti, Zr, V, Nb, Cr, Zn, B, Al, Ga, Ge, and Sn. 
     
     
         24 . The powder of  claim 18 , wherein the compound is characterized by the formula Li u M v (XO 4 ) w  with u=1, 2 or 3; v=1 or 2; w=1 or 3; M has a formula Ti a V b Cr c Mn d Fe e Co f Ni g Sc h Nb i  with a+b+c+d+e+f+g+h+i=1 and X is P x-1 S x  with 0≦x≦1. 
     
     
         25 . The powder of  claim 18 , wherein the compound is characterized by the formula Li 1+x M m (XO 4 ) n , wherein 0<x≦0.2; m=1; and 1≦n≦1.05; and M comprises a transition metal selected from the group consisting of iron, manganese, vanadium, titanium, molybdenum, niobium, tungsten, zinc and mixtures thereof. 
     
     
         26 . The powder of  claim 18 , wherein I 1360 /I 1580  is at most 2.10. 
     
     
         27 . The powder of  claim 18 , wherein the layer comprising the carbonaceous material has a thickness of at least 2 nm. 
     
     
         28 . The powder of  claim 18 , wherein said Li a M m (XO 4 ) n  has a crystal size, measured by Rietveld refinement of XRD data, of at most 90 nm. 
     
     
         29 . An electrochemically active powder comprising particles containing a compound represented by formula Li 1+x FePO 4  wherein x is at least 0.01, said particles being at least partially coated with a layer comprising a carbonaceous material and having a thickness of at least 3 nm, said carbonaceous material comprising a highly ordered graphite, wherein said highly ordered graphite has a ratio (I 1360 /I 1580 ) of a peak intensity (I 1360 ) at 1360 cm −1  to a peak intensity (I 1580 ) at 1580 cm −1 , obtained by Raman spectrum, of at most 3.00. 
     
     
         30 . An electrode material comprising a composition containing the electrochemically active powder of  claim 18 , and a binder. 
     
     
         31 . An electrochemical cell containing at least two electrodes and at least one electrolyte, wherein at least one of the electrodes is the electrode of  claim 30 . 
     
     
         32 . A battery and devices containing thereof, wherein said battery contains at least one of the electrochemical cells of  claim 31 , and wherein said devices are chosen from the group consisting of portable electronic devices, portable computers, tablets, mobile phones, electrically powered vehicles and energy storage systems. 
     
     
         33 . A method for making a carbon coated electrochemically active powder, said powder comprising particles containing a compound represented by formula Li a M m (XO 4 ) n  wherein 0<a≦3.2; 1≦m≦2; and 1≦n≦3; M comprises at least one transition metal and optionally at least one non-transition metal; and X is selected from the group consisting of S, P and Si; said method comprising:
 i. providing a mixture of the following precursors
 a. a source of Li; 
 b. a source of an element M; 
 c. a source of an element X; and 
 d. a source of carbon; 
 
 
       wherein the sources of elements A, M and X are introduced in whole or in part in the form of compounds having the at least one source element;
 ii. heating up said mixture in a sintering chamber to a sintering temperature of at least 500° C. and sintering said mixture at said sintering temperature for a first period of time, wherein a stream of inert gas is provided to said chamber; 
 iii. continuously injecting steam in said sintering chamber before or during the heating up, and before or during the sintering the mixture, for an injection time; thereby producing particles containing said compound wherein the particles are at least partially coated with a carbonaceous material containing a highly graphitized carbon; and 
 iv. cooling said powder. 
 
     
     
         34 . A method according to  claim 33 , wherein X is P.