Graphene‐based Activated Carbon Composites for High Performance Lithium‐Sulfur Batteries

Abstract

The increasing demand for electrical energy storage requires the exploration of alternative battery chemistries that overcome the limitations of the current state-of-the-art lithium-ion batteries. In this scenario, lithium-sulfur batteries stand out for their high theoretical energy density. However, several inherent limitations still hinder their commercialization. In this work, we report the synthesis and study of two high-performance activated carbon-based materials that allow to overcome the most challenging limitations of sulfur electrodes, i. e., low electronic conductivity and the polysulfide shuttle effect. The two tailored nanomaterials are based on porous carbon structures mixed with conductive reduced graphene oxide, one derived from an organic waste and the other from an organic synthetic route. These structures not only feature excellent individual properties, but also present excellent performance when implemented in batteries, related to their superior conductivity and polysulfide trapping ability, allowing to obtain improved rate capacity and high sulfur loading cycling. Additionally, we demonstrate the scalability of the best performing material by the assembly of high-performance pouch cells.

High Energy Density Lithium–Sulfur Batteries Based on Carbonaceous Two-Dimensional Additive Cathodes

“…Moreover, in the case of graphene-based activated carbon cathodes, the uniform and 2D flat-shaped structures of ResFArGO are in close contact with KJ600@S agglomerates, providing a high electrical conductivity typically found in graphene-based activated materials. These SEM images confirm the packing properties depending on the selected additives, highlighting the composition containing ResFArGO in which the mechanical properties found for the purely graphenecontaining cathodes 39 are also observed when it is combined with KJ600. Finally, as displayed in Figure 2a(iii), energydispersive spectrometry (EDS) elemental mapping of S of the all-prepared electrodes reveals the excellent distribution of the active material within the cathode without the presence of any S clusters, confirming the suitability of the selected S infiltration technique.…”

“…The main difference is that while in the case of the ResFArGO, this process was performed over the carbon mixture, in the case of the cathode with CAs, the melt diffusion was only done with KJ600, and the carbon additives were subsequently added. For the positive electrode preparation, the procedure detailed in our previous work was followed …”

“…For the positive electrode preparation, the procedure detailed in our previous work was followed. 39 …”

“…For the positive electrode preparation, the procedure detailed in our previous work was followed. 39 Two positive electrodes with different sulfur loadings were prepared depending on their final application: medium mass loading electrodes (∼3 mg S cm −2 ) used for the C-rate test and high mass loading electrodes (∼4 mg S cm −2 ) used for the long-cycling test. Electrodes of different sizes were used depending on the battery cell used for the testing: 13 mm in diameter for coin cell and 37.5 × 54 mm electrodes for pouch cell assembly.…”

“…In this regard, our team recently developed a graphene-based activated carbon which was used as the main carbon in the Li–S cathode, allowing the processing of high sulfur loading cathodes with high capacity and high energy density even at the pouch level. 39 Despite the outstanding electrochemical performance, the high production cost is still one of their main limitations. However, its use as an additive in small amounts could effectively reduce the cost of electrode production and make it profitable for LSB manufacturing.…”