Li/Na-ion battery anode materials

摘要

An active electrode material disclosed in the application is expressed by the general formula [M1]x[M2](1-x)[Nb]y[O]z, wherein M1 and M2 are different. In this one particular aspect the material is selected from the group consisting of [M1xMo(1-x)]Nb12O(33-33α), [M1xW(1-x)]Nb12O(33-33α), [M1xV(1-x)]Nb9O(25-25α), [M1xZr(1-x)]Nb24O(62-62α), [M1xW(1-x)]7Nb4O(31-31α) and [M1xW(1-x)]9Nb8O(47-47α), wherein M1 represents one or more of Ti, Mg, V, Cr, W, Zr, Nb, Mo, Cu, Fe, Ca, K, Ni, Co, Al, Sn, Mn, Ce, Si, Sb, Y, La, Ta, Zn or Cd, and wherein 0 < x < 0.5 (i.e. M1 comprises the minor proportion in the mixed cation) and 0 ≤ α ≤ 0.05 (i.e. the material may or may not be oxygen depleted). Another disclosed aspect relates to an oxygen-depleted mixed niobium oxide selected from the group consisting of MoNb12O(33-33α),WNb12O(33-33α), VNb9O(25-25α), ZrNb24O(62-62α), W7Nb4O(31-31α) and W9Nb8O(47-47α), wherein 0 < α ≤ 0.05 (i.e. the material must be oxygen depleted). It is disclosed that adapting known mixed niobium oxides to either include the mixed cations of the first aspect or to be oxygen-depleted as in the second aspect improves electrochemical behaviour. Such materials can be used as electrode active materials in lithium-ion or sodium-ion batteries.