1. Sulfur-Rich Cathode Materials for High-Energy Batteries Achievement A family of new lithium polysulfidophosphate (LPSP) compounds enables stable cycling of all-solid-state lithium- sulfur (Li-S) batteries with long lifespans. The excellent cyclability demonstrated in this research is attributed to the high ionic conductivity of LPSP, which is 10 7 times higher than Li 2 S, the most conductive species in conventional sulfur cathodes. Significance Li-S batteries have a high theoretical energy density 5 times higher than that of the lithium-ion batteries. Although promising, Li-S batteries have an intrinsic short lifespan. The all-solid-state Li-S overcome the cycle-life limit of the S cathode and imparts the safe cycling of metallic lithium anode. Research Details CNMS Capability: Synthesis and characterization of cathode materials; battery testing. Li 3 PS 4 reacts with elemental S and yields lithium polysulfidophosphate (LPSP) compounds with a general formula of Li 3 PS 4+n (0<n<9). LPSP compounds are superionic conductors. The log scale of the ionic conductivity (log σ) of LPSP follows a linear relationship with the number of sulfur atoms (n). All-solid-state batteries have an excellent cycling performance with a cell configuration of LPSP as the cathode, Lithium metal as the anode, and Li 3 PS 4 as the electrolyte. Zhan Lin, Zengcai Liu, Wujun Fu, Nancy J Dudney, and Chengdu Liang Angewandte Chemie-International Edition, DOI: 10.1002/anie.201300680 CNMS User Project Highlight Figure 2. Temperature dependency of ionic conductivity of Li 3 PS 4+5 and Li 2 S. Figure 1. Cycling performance of an all-solid-state Li-S battery using LPSP as the cathode material. Work was performed at CNMS and MSTD in ORNL

2. Inexpensive, High-Energy Batteries Achievement A new family of lithium polysulfidophosphate (LPSP) compounds has been discovered for high energy lithium-sulfur batteries. The battery uses solid electrolytes that are intrinsically safer than the liquid electrolytes used in conventional lithium-ion batteries. The new battery structure last longer than conventional batteries. Significance and Impact Harvesting of intermittent renewable energies to a stable supply of electricity needs large scale storage of electricity that are safe, low cost, and high energy-density. Long-lasting lithium-sulfur battery technology has been demonstrated based on a low –cost material of elemental sulfur. The all- solid-state configuration ensures a safe operation of battery. Research Details Li 3 PS 4 reacts with elemental S and yields lithium polysulfidophosphate (LPSP) compounds with a general formula of Li 3 PS 4+n (0<n<9). The lithium-ions are highly mobile in this new family of compounds. The high ionic conductivity of these compounds enables a long cycle-life of lithium-sulfur batteries. Zhan Lin, Zengcai Liu, Wujun Fu, Nancy J Dudney, and Chengdu Liang Angewandte Chemie-International Edition, DOI: 10.1002/anie.201300680 CNMS User Project Highlight Figure 2. Temperature dependency of ionic conductivity of Li 3 PS 4+5 and Li 2 S. Figure 1. Cycling performance of an all-solid-state Li-S battery using LPSP as the cathode material. Work was performed at CNMS and MSTD in ORNL