Auto-ignition route to thermoelectric oxide NaxCo2O4 powder with high compactibility

The ultra fine powder of thermoelectric oxide NaxCo2O4 has been synthesized via an auto-ignition route following with airflow shatter process, which has the flaky shape in different nominal x compositions. Single γ-phase NaxCo2O4 crystal structure was obtained in varying Na contents of 1.4–1.8 at the calcining temperature of 1153 K. The airflow shatter process was found to be beneficial for obtaining uniform particles with smaller the average size and larger BET surface area. The compaction module and the nonlinear exponent of powder compaction are about 4.037 MPa and 4.368 calculated form Huang Peiyunʹs compacting equation, respectively, which reveals that the NaxCo2O4 powder has high compactibility.