A lithium (Li) ion battery includes a first electrode with a second electrode, and a shutdown polymer additive on an outer surface of the first electrode. The shutdown polymer additive includes at least two polyethylene layers, each polyethylene layer comprising a plurality of polyethylene microspheres. Each polyethylene microsphere is wrapped with carbon nanotubes. The polyethylene microspheres interconnect with each other such that the carbon nanotubes form a conductive network. The polyethylene layers are provided at predetermined areas of the outer surface of the first electrode.