Baton has explosive secret power (7)
I believe the answer is:
sceptre
'baton' is the definition.
(I have seen 'Royal baton ' mean 'sceptre' so perhaps 'baton' could also mean 'sceptre')
'explosive secret power' is the wordplay.
'explosive' is an anagram indicator.
'power' becomes 'p' (symbol in physics).
'secret'+'p'='secretp'
'secretp' is an anagram of 'SCEPTRE'.
'has' is the link.
(Other definitions for sceptre that I've seen before include "Royal staff (paired with 2 down)" , "Monarch's ceremonial staff" , "Respect (anag) -- symbol of ruler's authority" , "Ruler's staff" , "Official staff" .)