NOVELTY - A lithium ion (Li-ion) battery module, comprises: a container comprising one or more partitions that define a set of compartments within the container, where each of the set of compartments is configured to receive and hold a prismatic Li-ion electrochemical cell element and electrolyte; and a cover configured to be disposed over the container to close the compartments; where the container comprises a polymer blend comprising a base polymer and a nanomaterial blended into the base polymer.    USE - A lithium ion (Li-ion) battery module used as a power source for vehicles.    ADVANTAGE - The lithium ion (Li-ion) battery module is cost-efficient, and has improved thermal activity.    DETAILED DESCRIPTION - A lithium ion (Li-ion) battery module, comprises: a container comprising one or more partitions that define a set of compartments within the container, where each of the set of compartments is configured to receive and hold a prismatic Li-ion electrochemical cell element and electrolyte; and a cover configured to be disposed over the container to close the compartments; where the container comprises a polymer blend comprising a base polymer and a nanomaterial blended into the base polymer, where the base polymer is electrically nonconductive and where the nanomaterial is configured to enhance the impermeability of the container to reduce ingress of moisture into the compartments and to reduce egress of the electrolyte from the compartments. INDEPENDENT CLAIMS are included for:    (1) a Li-ion battery cell which comprises: a housing configured to receive and hold a Li-ion electrochemical cell element and electrolyte, where the housing comprises a nanomaterial applied to an electrically nonconductive base polymer material, where the nanomaterial enhances the impermeability of the housing to reduce ingress of moisture and to reduce egress of the electrolyte; and    (2) a method for manufacturing the Li-ion battery module, which involves: forming a container configured to receive and hold a Li-ion electrochemical cell element, where the container comprises at least an electrically nonconductive base polymer; and applying a nanomaterial to the base polymer of the container.