Li3-xMxN (M = Co, Ni, Cu) with hexagonal symmetry, P6/mmm, was prepared by heating a mixture of Li3N and metallic powder in a nitrogen gas stream. Solid solutions of Li3-xMxN are formed in the range of 0 less than or equal to x less than or equal to 0.5, 0 less than or equal to x less than or equal to 0.6, and 0 less than or equal to x less than or equal to 0.3 for M=Co, Ni and Cu, respectively, The cycle performance in an Li/Li3-xMxN cell was studied in the cell voltage range between 0.01 and 1.5 V. The lithium ion is easily cycled over a wide range of 0.0 less than or equal to z less than or equal to 1.0 in Li3-x-zCoxN and is also cycled fairly well Li3-x-zCuxN with the cell voltage range between 0 and 1.1 V., It is characteristic that the charge and discharge curves of the second cycle differ from the first one. On the other hand, in the Li/Li3NixN cell, the lithium ion is only cycled in a narrow range of 0.0 less than or equal to z less than or equal to 0.5 between 0.01 and 1.5 V, white the charge and discharge curves of the second cycle are almost similar to the first one.