| abstract |
Provided is a lithium secondary battery containing an anode, a cathode, a porous separator/electrolyte element disposed between the anode and the cathode, and a cathode-protecting layer bonded or adhered to the cathode, wherein the cathode-protecting layer comprises a lithium ion-conducting polymer matrix or binder and inorganic material particles that are dispersed in or chemically bonded by the polymer matrix or binder and wherein the cathode-protecting layer has a thickness from 10 nm to 100 μm and the polymer matrix or binder has a lithium-ion conductivity from 10−8 S/cm to 5×10−2 S/cm. Additionally or alternatively, there can be a similarly configured anode-protecting layer adhered to the anode. Such an electrode-protecting layer prevents massive internal shorting from occurring even when the porous separator gets melted, contracted, or collapsed under extreme temperature conditions induced by, for instance, dendrite or nail penetration. |