Improving the Performance of Lithium Manganese Phosphate Through Divalent Cation Substitution

Improving the Performance of Lithium Manganese Phosphate Through Divalent Cation Substitution Guoying Chen*' and Thomas J. Richardson* Environmental Energy Technologies Division Lawrence Berkeley National Laboratory Berkeley, California 94720 USA z Abstract Highly crystalline samples of LiMnP04 and its analogs with partial substitution of M n by divalent M g , Cu, Zn, and N i were prepared by hydrothermal synthesis and characterized by x-ray diffraction and infrared spectroscopy. Chemical oxidation produced two-phase mixtures of the initial phases LiMn(i. )M P04 and the delithiated y y forms, LiyMn(i_y)M P04, all with the olivine structure. The extent of oxidation depended y upon the quantity of oxidizing agent used and on the identity of the substituent ions. Mg, N i and Cu were found to increase the level of delithation relative to that in pure LiMnPCv}. M g was also shown to reduce the tendency of the oxidized phase to absorb water. Electrochemical Society Active Member z E-mail: gchen@lbl.gov