The invention relates to the field of
electrochemistry, and particularly relates to a
lithium ion battery. One aspect of the invention provides a
lithium ion battery. The
lithium ion battery comprisesa positive
pole piece, a negative
pole piece, an
isolation membrane and an
electrolyte, and is characterized in that the negative
pole piece comprises a negative active material layer containing a negative active material, the
electrolyte comprises an
electrolyte lithium salt, the electrolyte lithium salt comprises a first lithium salt, the first lithium salt is selected from
fluorine-containingsulfimide lithium salt, and the first lithium salt and the negative pole piece meet a relational expression (1). According to the invention, the
fluorine-containing sulfimide lithium salt is used as the electrolyte of the first lithium salt, so that too fast impedance increase or too large
concentration polarization of the battery can be effectively inhibited, the high-temperature
advantage and the high-
conductivity advantage of the
fluorine-containing sulfimide lithium salt can be fully exerted, the formed battery is relatively low in
floating charge physical resistance increase rate, the safety problems such as lithium
precipitation in the middle and later periods of circulation are avoided, and finally the excellent properties of high safety performance, long cycle life and good high-temperature storage are achieved.