The state of Li ions was investigated in electrochemically doped poly(
p-phenylene) (PPP). Two kinds of Li cations exist possessing different
mobility. The fraction of the more mobile cations increases with temp
erature but does not exceed 0.5. For the PPP-Li system, the ion mobili
ty is not too high in contrast to the PPP-AsF6- (BF4-) system and up t
o 400 K there are no chemical reactions leading to polymer destruction
.