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

Wu, Qingping; Zhou, Xuejun; Xu, Jun; Cao, Fahai; Li, Chilin · ACS Nano · 2019

basic_science · Level V

Where this comes from

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 MgCl<sub>2</sub> hydrate template <i>via</i> a facile ionothermal method. It allows a homogeneous spatial distribution of S/Li<sub>2</sub>S 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<sup>-1</sup> 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<sup>-2</sup> even under an ultrahigh sulfur loading up to 9.7 mg cm<sup>-2</sup>.