Ex situ synchrotron XRD of the final calcined material in each case (Figure ) demonstrates how reaction pathway tunes LMR structure. LL-LMR exhibits a greater monoclinic character (SI Figure Particle morphology is also more heterogeneous for the LL-LMR pathway. While many of the LL-LMR primary particles exhibit similar morphology to the SL-LMR, a small subset of the LL-LMR particles observed via SEM exhibit a larger and more faceted primary particle morphology (See SI Figures and). As the surface energy of some crystal facets is ). Wavelength λ=0.72946 Å. Li 2 CO 3 particle size tunes the presence/absence of rapid mass loss at the Li 2 CO 3 melting point. Note the TGA and dm/dT traces for SL-LMR and AR-LMR are also shown in Figure , repeated here for comparison to the LL-LMR case, which continues the trend between the SL-LMR and AR-LMR materials. The LL-LMR material exhibits greater superstructure than the SL-LMR material (inset). reduced in a Li 2 CO 3 melt, this type of faceting is expected from a molten salt synthesis. We conclude that the particles exhibiting this morphology grew within the Li 2 CO 3 melt. The fraction of faceted particles is low enough to realistically preclude effective quantification from SEM imaging alone. Consistently, the AR-LMR material exhibits a lower BET surface area than the SL-LMR material only after Li 2 CO 3 melts, supporting that rapid growth of relatively large particle occurs after Li 2 CO 3 melting. Finally, we compare the electrochemical behavior of SL-LMR and the LL-LMR, focusing on the two extremes in Li 2 CO 3 particle size to make any trend more apparent. Figure shows the SL-LMR material exhibits higher first-cycle charge capacity, with most of this increase coming within the anionic redox region at >4.6 V vs. Li/Li + , and higher first cycle discharge capacity. As capacity in these regions on first charge is typically attributed to oxygen release, these differences suggest different oxygen release behavior between the LL-LMR and SL-LMR materials. However, over extended activation, the voltage curves of the SL-LMR and LL-LMR materials converge. A rate test performed after 13 extended activation cycles (details of cycling protocol available in SI Figure ) confirms that the kinetic, as well as pseudo-open circuit voltage, behavior of the materials converges following activation. Figure and show that their hysteresis and discharge capacity as a function of C-rate are also nearly identical.