| 摘要 |
PROBLEM TO BE SOLVED: To provide an active material in which charge/discharge capacity of a composite oxide including Na and Mn is increased, and a secondary battery using the active material.SOLUTION: When Al of 30 atom% or less relative to the total amount of Mn and the Al is made to form a solid solution in a composite oxide of Na and the Mn, an activity as an active material is improved, so that ion conductivity is increased and more ions can be inserted and desorbed. By including such an active material as a positive electrode active material, a secondary battery has higher charge/discharge capacity as compared with a secondary battery using a composite oxide of Na and Mn without including Al. |
