A novel battery separator coated by a europium oxide/carbon nanocomposite enhances the performance of lithium sulfur batteries.

Lithium sulfur (Li-S) batteries represent one of the most promising future power batteries due to their remarkable advantages of low cost and ultrahigh theoretical energy density. However, the commercial applications of Li-S batteries have long been plagued by the shuttling effect of polysulfides and sluggish redox kinetics of these species. Herein, we designed a novel battery separator coated by a europium oxide-doped porous Ketjen Black (Eu2O3/KB) and tested its performance for the Li-S batteries for the first time. Experimental results and theoretical calculations reveal that the improved electrochemical performance can be attributed to the presence of Eu2O3. The strong binding effect between Eu2O3 and polysulfides is demonstrated in two aspects: (1) there exist strong interactions between Eu2O3 as a Lewis acid and polysulfides of strong Lewis basicity; (2) Eu2O3 with oxygen-vacancy defects provides active sites for catalyzing polysulfide conversion and polysulfide trapping. Thus, a Li-S battery with the Eu2O3/KB modified separator delivers highly stable cycling performance and excellent rate capability, with the capacity decay ratio of merely 0.05% per cycle under 1 C rate during 500 cycles, and high specific capacity of 563 mAh g-1 at 3 C rate. This work offers a meaningful exploration of the application of rare earth oxides for the modification of the separator towards high performance Li-S batteries.

Rational design of Co4N nanoparticle loaded porous carbon as a sulfur matrix for advanced lithium-sulfur batteries.

Lithium-sulfur (Li-S) batteries have a high specific capacity of 1675 mAh g-1 and are considered to be a promising next-generation energy storage system. A sulfur host for loading Co4N nanoparticles into porous carbon has been designed as the cathode for high-performance Li-S batteries. The porous carbon successfully confines sulfur and Co4N in the pores, and the synergistic effect of physical and chemical adsorption can effectively inhibit the dissolution and diffusion of polysulfides. Besides, the Co4N nanoparticles can also catalyze the redox reaction kinetics. At a current density of 0.5 C, S@KJ-Co4N cathodes deliver a high specific discharge capacity of 958.3 mAh g-1 and retain at 784.0 mAh g-1 after 200 cycles, corresponding to a decay rate of 0.09% per cycle. It is believed that this work can provide a promising strategy for the design of many energy storage systems.

Extraction of Lithium from Single-Crystalline Lithium Manganese Oxide Nanotubes Using Ammonium Peroxodisulfate.

In this work, a spinel single-crystalline Li1.1Mn1.9O4 has been successfully synthesized using ß-MnO2 nanotubes as the self-sacrifice template. The tubular morphology was retained through solid-state reactions, attributed to a minimal structural reorganization from tetragonal ß-MnO2 to spinel Li1.1Mn1.9O4. The materials were investigated as sorbents for lithium recovery from LiCl solutions, recycled using H2SO4 and (NH4)2S2O8. Li1.1Mn1.9O4 nanotubes exhibited favorable lithium extraction behavior due to tubular nanostructure, single-crystalline nature, and high crystallinity. (NH4)2S2O8 eluent ensures the structural stability of Li1.1Mn1.9O4 nanotube, registering a Li+ adsorption capacity of 39.21 mg g-1 (∼89.73% of the theoretical capacity) with only 0.08% manganese dissolution after eight adsorption/desorption cycles, compared to that of 1.21% for H2SO4. It reveals the degradation of sorbent involves with the volume change, Mn reduction, and Li/Mn ratio depletion. New strategies, based on nanotube adsorbent and (NH4)2S2O8 eluent, can extract lithium ions at satisfactorily high degrees while effectively minimizing manganese dissolution.