As　one　of　the　most　efficient　electrochemical　energy　storage　devices,　the　energy　density　of　lithium-ion　batteries　(LIBs)　has　been　extensively　improved　in　the　past　several　decades.　However,　with　increased　energy　density,　the　safety　risk　of　LIBs　becomes　higher　too.　The　frequently　occurred　battery　accidents　worldwide　remind　us　that　safeness　is　a　crucial　requirement　for　LIBs,　especially　in　environments　with　high　safety　concerns　like　airplanes　and　military　platforms.　It　is　generally　recognized　that　the　catastrophic　thermal　runaway　(TR)　event　is　the　major　cause　of　LIBs　related　accidents.　Tremendous　efforts　have　been　devoted　to　coping　with　the　TR　concerns　in　LIBs,　and　thus　enhance　battery　safety.　This　review　first　gives　an　introduction　to　the　fundamentals　of　LIBs　and　the　origins　of　safety　issues.　Then,　the　authors　summarize　the　recent　advances　to　improve　the　safety　of　LIBs　with　a　unique　focus　on　thermal-responsive　and　fire-resistant　materials.　Finally,　a　perspective　is　proposed　to　guide　future　research　directions　in　this　field.　It　is　anticipated　this　review　will　stimulate　inspiration　and　arouse　extensive　studies　on　further　improvement　in　battery　safety.　©　2021　Wiley-VCH　GmbH.