In recent years,lithium ion (Li-ion) batteries have served as significant power sources in portable electronic devices and electric vehicles because of their high energy density and rate capability.There are growing concerns towards the safety of Li-ion batteries,in which thermal conductivities of anodes,cathodes,electrolytes and separator play key roles for determining the thermal energy transport in Li-ion battery.In this review,we summarize the state-of-the-art studies on the thermal conductivities of commonly used anodes,cathodes,electrolytes and separator in Li-ion batteries,including both theoretical and experimental reports.First,the thermal conductivities of anodes and cathodes are discussed,and the effects of delithiation degree and temperature of materials are also discussed.Then,we review the thermal conductivities of commonly used electrolytes,especially on solid electrolytes.Finally,the basic concept of interfacial thermal conductance and simulation methods are presented,as well as the interfacial thermal conductance between separator and cathodes.This perspective review would provide atomic perspective knowledge to understand thermal transport in Li-ion battery,which will be beneficial to the thermal management and temperature control in electrochemical energy storage devices.