An electrochemical cell for a lithium battery includes a negative electrode, a positive electrode, a polymeric separator, and composite flame retardant particles including a particulate host material and a flame retardant material carried by the particulate host material. The composite flame retardant particles may be positioned within the electrochemical cell along a lithium-ion transport path or an electron transport path that extends through or between one or more components of the electrochemical cell. The composite flame retardant particles may be positioned within polymeric portions of a laminate structure that defines a housing in which the electrochemical cell is enclosed.