High Volumetric Energy Density Sulfur Cathode with Heavy and Catalytic Metal Oxide Host for Lithium–Sulfur Battery

Abstract

For high-energy lithium-sulfur batteries, the poor volumetric energy density is a bottleneck as compared with lithium-ion batteries, due to the low density of both the sulfur active material and sulfur host. Herein, in order to enhance the volumetric energy density of sulfur cathode, a universal approach is proposed to fabricate a compact sulfur cathode with dense materials as sulfur host, instead of the old-fashioned lightweight carbon nanomaterials. Based on this strategy, heavy lanthanum strontium manganese oxide (La 0.8 Sr 0.2 MnO 3), with a high theoretical density of up to 6.5 g cm −3 , is introduced as sulfur host. Meanwhile, the La 0.8 Sr 0.2 MnO 3 host also acts as an efficient electrocatalyst to accelerate the diffusion, adsorption, and redox dynamics of lithium polysulfides in the charge-discharge processes. As a result, such S/La 0.8 Sr 0.2 MnO 3 cathode presents high gravimetric/volumetric capacity and outstanding cycling stability. Moreover, an ultra-high volumetric energy density of 2727 Wh L −1-cathode is achieved based on the densification effect with higher density (1.69 g cm −3), which is competitive to the Ni-rich oxide cathode (1800-2160 Wh L −1) of lithium-ion batteries. The current study opens up a path for constructing high volumetric capacity sulfur cathode with heavy and catalytic host toward practical applications of lithium-sulfur batteries. Achieving higher energy density is the continuous driving force for the development of secondary batteries. Among all the commercial secondary batteries, lithium-ion batteries (LIBs) possess high gravimetric and volumetric energy densities, almost approaching their limitation of energy densities based on the inherent intercalation chemistry. [1] Beyond LIBs, lithium-sulfur (Li-S) battery has attracted considerable attention due to the high theoretical gravimetric and volumetric energy densities of 2600 Wh kg −1 and 2800 Wh L −1 , respectively.

Constructing high gravimetric and volumetric capacity sulfur cathode with LiCoO2 nanofibers as carbon-free sulfur host for lithium-sulfur battery

“…While a higher density of the cathode (>1.3 g cm −3 ) generally gives rise to high W V and low W G , which is more common for the compact cathode. For the latter case, the conversion of sulfur in the densified structure is inevitably inhibited because of the difficulty for electrolyte infiltration or limited effective surface area for Li 2 S/L 2 S deposition [32,[45][46]. Therefore, a tradeoff between the cathode density and sulfur utilization should be achieved.…”

“…The low W V is a critical challenge for the practical application of Li-S battery with a confined space, and might undermine its possible market interests in electric vehicles [31]. Therefore, W V should be paid more attention to in order to fully achieve the potential of Li-S battery [31][32][33].…”

“…Generally, calendering technology could tune the cathode porosity and increase the density, leading to an improved volumetric capacity [43][44]. However, the resultant dense structure by pressure often slows down the sulfur redox due to the poor electrolyte wetting and Li 2 S 2 /Li 2 S deposition, which are harmful to the gravimetric capacity [32,[45][46].…”

“…The host materials could be classified into two categories in terms of density: heavy one with higher density, and light one with lower density as compared with sulfur. By introducing heavy metal oxides or sulfides, the high volumetric capacity could be obtained for the compact S-composites [32,[47][48][49][50][51][52][53] . Carbon nanotubes (CNT) were bought from Nanjing XFNANO Materials Tech.…”

Mass Production of Calendering-Compatible Sulfur-Rich Secondary Particles via Hail-Inspired Nanostorm Technology for Advanced Metal-Sulfur Batteries

“…A high tap density of electrode particles will favor the fabrication of compact electrodes with high E v . 37 . From the Fig.…”