Adenine Derivative Host with Interlaced 2D Structure and Dual Lithiophilic–Sulfiphilic Sites to Enable High-Loading Li–S Batteries

Abstract

How to simultaneously restrain the loss of active species and facilitate the conversion reaction under high S loading condition is the key to solve the commercialization of Li–S batteries. For this system, the availability of raw materials and simplicity (high efficiency) of synthetic strategies are also important factors. Herein, we propose an interlaced two-dimensional (2D) carbon material as advanced Li–S cathode host characterized by corrugated monolithic morphology and Co/N dopants as dual lithiophilic–sulfiphilic sites. This 2D structure is derived from a cheap biomass precursor, adenine, with bonding interaction with a MgCl2 hydrate template via a facile ionothermal method. It allows a homogeneous spatial distribution of S/Li2S deposits and strong adsorbability and enhanced conversion kinetics for polysulfides. Benefiting from the synergistic effects of corrugated 2D conductive matrix and embedded heteroatom/nanodot catalyst, the resultant sulfur cathode releases a high specific capacity of 1290.4 mA h g–1 at 0.2 C, small capacity fading rate of 0.029% per cycle over 600 cycles at 2 C, superior rate performance up to 20 C, and considerable areal capacity retention of 6.0 mA h cm–2 even under an ultrahigh sulfur loading up to 9.7 mg cm–2.

Highly Stable Lithium−Sulfur Batteries Promised by Siloxene: An Effective Cathode Material to Regulate the Adsorption and Conversion of Polysulfides

“…Figure 5a displays the cyclic voltammetry (CV) profiles comparison between Si/G and pure-G cathodes at a scan rate of 0.1 mV s −1 . Two reversible cathodic peaks attribute to the solid-to-liquid phase transformation (from elemental sulfur to soluble polysulfides) and following conversion from soluble polysulfides to solid-state Li 2 S 2 /Li 2 S, and one anodic peak is related to the reconversion of Li 2 S/Li 2 S 2 to sulfur, [6,51] which is in harmony with the analysis of galvanostatic charge/discharge profiles. All peaks of Si/G cathode are sharper and possess stronger peak current density in contrast to those of pure-G cathode, suggesting better redox reactivity and higher utilization of active S species.…”

“…Among the emerging battery technologies, lithium–sulfur batteries (LSBs) have attracted extensive attention owing to unparalleled features including high energy density, non‐toxicity, and low cost 4,5. However, the practical implementation of LSBs, close to commercial application, is plagued with several dilemmas, including insulating nature of sulfur and its final discharge products, highly soluble polysulfides and large volume fluctuation upon lithiation/delithiation process 6–8. Among these intractable issues, dissolved polysulfides in organic electrolytes and their subsequent inter‐electrode migration, namely, shuttling effect, are particularly detrimental to the performances of LSBs, which could lead to rapid capacity attenuation, inefficient sulfur utilization, low coulombic efficiency, and worse still, lithium dendrite issues 9,10.…”

“…[4,5] However, the practical implementation of LSBs, close to commercial application, is plagued with several dilemmas, including insulating nature of sulfur and its final discharge products, highly soluble polysulfides and large volume fluctuation upon lithiation/delithiation process. [6][7][8] Among these intractable issues, dissolved polysulfides in organic electrolytes and their subsequent inter-electrode migration, namely, shuttling effect, are particularly detrimental to the performances of LSBs, which could lead to rapid capacity attenuation, inefficient sulfur utilization, low coulombic efficiency, and worse still, lithium dendrite issues. [9,10] Besides, the sluggish electrochemical conversion kinetics of soluble polysulfides can cause grievous polarization effect, resulting in inferior rate performance.…”

Recent progress on biomass‐derived ecomaterials toward advanced rechargeable lithium batteries

“…To further rationally construct electrodes with interconnected conductive network, bio‐derived carbon frameworks combined with other low‐dimensional (1D and 2D) conductive fragments (such as graphene, carbon nanotube, etc.) are desired . The 2D nanosheet or 1D nanotube morphology are beneficial for fast electron transfer; and meanwhile, the interconnected framework promotes rapid ion transport, thus facilitates reversible electrochemical redox.…”

“…are desired. [110][111][112][113][114] The 2D nanosheet or 1D nanotube morphology are beneficial for fast electron transfer; and meanwhile, the interconnected framework promotes rapid ion transport, thus facilitates reversible electrochemical redox.…”