As next generation space suit concepts enable extravehicular activity (EVA) mission capability to extend beyond anything currently available today, revolutionary advances in life support technologies are required to achieve anticipated NASA mission profiles that may measure years in duration and require hundreds of sorties. Since most life support systems require power, increased mass and volume efficiency of the energy storage materials can have a dramatic impact on reducing the overall weight of next generation space suits. This paper details the development of a multifunctional fiber battery to address these needs.The fiber battery is based on a solid-state lithium technology that is fully rechargeable and provides: (1) greater than 10,000 cycles at 100% depth of discharge at 95% of initial capacity; (2) high rates (full capacity charge or discharge in ∼10 minutes); (3) improved safety and packaging efficiency by eliminating liquid electrolytes; and (4) flexible integration schemes that allow the battery to be fabricated on/in space suit materials or components. By depositing the battery on existing space suit fibers (e.g., scrim fibers in the thermal micro-meteoroid garment (TMG) layer) parasitic mass (inactive material) is eliminated, leading to dramatically higher energy densities (∼400 Wh/kg). The high surface area to volume packing efficiency of fiber batteries compared to planar configurations further enhances the energy storage efficiency.