** Shares of NOVONIX NVX.AX fall 6.9% TO A$0.605, their lowest levels since Dec 20

** The battery materials firm's CEO Chris Burns steps down after more than four years in the role

** Current CFO Robert Long will act as interim CEO until a permanent CEO is appointed

** Stock fell as much as 10% earlier in the day, touching their lowest level since Dec. 16

** Stock down 11.6% this year, as of last close

(Reporting by John Biju in Bengaluru)

((John.Biju@thomsonreuters.com;))