Electrocatalytic Cathodes Based on Cobalt Nanoparticles Supported on Nitrogen-Doped Porous Carbon by Strong Electrostatic Adsorption for Advanced Lithium–Sulfur Batteries

Abstract

Energy demands have increased rapidly over the previous decades, leading to new innovations in the energy storage field. One of the candidates for advanced energy storage is the lithium-sulfur battery. This Li−S battery is advantageous for its relatively high volumetric and gravimetric energy density and affordability. However, the widespread use and manufacturing of Li−S batteries are hampered by accelerated capacity decay upon cycling due to volume changes at the cathode, a "shuttle effect" of soluble lithium polysulfide (LPS) dissolution from cathode, and kinetically sluggish redox processes. In this study, we have designed a new and unique electrocatalytic cathode composed of ultrasmall cobalt nanoparticles embedded into nitrogen-doped porous carbon to host sulfur for the application of Li−S batteries via strong electrostatic adsorption (SEA). The large surface area (SA BET = 2355 m 2 g −1 ) and uniform distribution of ultrafine cobalt nanoparticles embedded in the nitrogen-doped carbon composite enables a high sulfur loading and significantly immobilizes soluble LPS during battery cycling while improving the electrochemical performance through catalytic effects. A sulfur doping of 71 wt % was attained, affording an initial specific capacity of 1219 mAh g −1 at 0.1 C (1C = 1675 mAh g −1 ) and Coulombic efficiency (99.1%) due to the cathodic multifunctional arrangements. At 0.5 C, the battery initially yields a specific capacity of 968 mAh g −1 and decreases to 858 mAh g −1 after 100 cycles. The battery delivered a specific capacity of 579 mAh g −1 after 300 cycles at 1 C and an exceptionally low capacity fade of 0.07% per cycle. This study demonstrates that SEA can be utilized to incorporate highly active metal nanoparticles into sulfur hosts to advance their electrocatalytic function and thereby advance Li−S batteries' stability.

Coal-Derived Activated Carbon for Electrochemical Energy Storage: Status on Supercapacitor, Li-Ion Battery, and Li–S Battery Applications

“…Most recently, it was observed that the Li–S batteries are a potential candidate for energy-storing devices due to their excellent energy density, indigenously available sulfur material, and low cost . Currently, researchers are focused on nanostructured composite materials and the development of battery design of Li–S batteries toward commercial application in electrochemical energy storage devices. − Kang et al proposed a facile method for the synthesis of hierarchical porous activated carbon from coal having a high surface area of 3343 m 2 g –1 , which is beneficial for polysulfides while also increasing sulfur loading. As can be observed in Figure , the coal-derived hierarchical porous activated carbon had a high specific capacity of 1390 mAh g –1 at 0.05 C, as well as outstanding rate performances and cyclic stability.…”

Insight into Lithium–Sulfur Batteries with Novel Modified Separators: Recent Progress and Perspectives

“…El-Kadri et al recently reported that ultrafine cobalt nanoparticles incorporated in a nitrogen-doped carbon composite allow for a high sulfur loading and considerably immobilize soluble lithium polysulfide (LPS) during battery cycling while increasing the electrochemical performance through catalytic effects …”

“…(b) Charge–discharge voltage profiles for the first 5 cycles of Co–BIDC/S at 0.1 C. The sulfur loading of Co–BIDC/S is 1.2 mg cm –2 . This figure was adapted with permission from ref . Copyright 2020 American Chemical Society.…”

“…El-Kadri et al recently reported that ultrafine cobalt nanoparticles incorporated in a nitrogen-doped carbon composite allow for a high sulfur loading and considerably immobilize soluble lithium polysulfide (LPS) during battery cycling while increasing the electrochemical performance through catalytic effects. 191 The high surface area of N-doped carbon allows for increased sulfur loading. Furthermore, the uniformly distributed cobalt nanoparticles serve as electrocatalytic sites for fast redox reactions, improving battery performance and durability against lithium polysulfide dissolution (Figure 27a).…”

“…The CoBIDC/S cell was tested using galvanostatic discharge−charge at various current rates ranging from 0.1 to 2 C (Figure 27b). The CoBIDC/S cell achieved a high specific discharge capacity of 1219 mAh g −1 and a reversible charge capacity of 1221 mAh g −1 , with a 99.9% coulombic efficiency at the rate of 0.1 C. 191 4.1. Summary and Perspectives.…”