requirements over the time of use, including variable rates, and pressures, and often most critical, temperatures. [2-4] The required low-temperature capabilities, shown in Figure 1, can present a critical roadblock toward the use of lithium-ion batteries. Commercial state-of-the-art batteries see noticeable drops in capacity retention and rate capability below 0 °C, and will rarely be recommended for use below −20 °C. [5] This limitation is defined by the kinetics of ion-transfer in solution; at low-temperatures, every stage of charge-transfer, from ion diffusion within the electrolyte and electrode materials to charge-transfer across the electrode-electrolyte interfaces, is significantly impeded. Low-temperature conditions, in which the environment itself has relatively limited thermal kinetic energy available, can present significant energetic hurdles within the chemical reaction pathway normally followed during charge and discharge at room temperature. In applications with recurring exposure to low-temperature conditions, particularly electric-vehicles and space applications, there is currently heavy reliance on secondary heating solutions coupled with thermal management systems in order to ensure consistent power delivery during operation. [6] Thermal management solutions can generally be classified as either internal, with thermal management elements integrated directly within the cell itself, or external, where thermal management solutions are applied to an entire pack or module. Internal solutions, including cells with integrated AC self-heating [7] or other internal self-heating structures, [8] are generally not feasible or practical to integrate within every cell used in an application given the added weight and complexity of such systems. [9] More commonly, external heating solutions are applied including thermal heating jackets or heating elements, warm-air heating, or liquid heat-transfer approaches. While these strategies may be more feasible to implement in practice than internal solutions, they also are accompanied by added weight, greater complexity, and reduced overall energy efficiency. [7,9] In space applications, there is often a reliance on radioisotope thermal generators (RTGs), which pair a thermoelectric generator with a decaying radioactive material to ensure consistent and reliable power generation energy. The waste heat from such systems is utilized to heat secondary systems, such Energy-dense rechargeable batteries have enabled a multitude of applications in recent years. Moving forward, they are expected to see increasing deployment in performance-critical areas such as electric vehicles, grid storage, space, defense, and subsea operations. While this at first glance spells great promise for conventional lithium-ion batteries, all of these usecases, unfortunately, share periodic and recurring exposures to extremely low-temperature conditions, a performance constraint where the lithiumion chemistry can fail to perform optimally. Next-generation chemistries employing alternative anodes...