One-Step In Situ Preparation of Polymeric Selenium Sulfide Composite as a Cathode Material for Enhanced Sodium/Potassium Storage

Abstract

Alkali metal−sulfur/selenium batteries have attracted much attention because they offer promising high energy density. However, the shuttle effect of the polysulfide dissolutions, poor electrical conductivity, and relatively large volume variations greatly hinder their potential applications. Herein, a novel organic carbon/selenium sulfide (OC/SeS 2 ) composite has been prepared by a one-step in situ method by heating the mixture of commercial polyacrylonitrile (PAN) with selenium sulfide powder in vacuum. The carbonized PAN matrix with an N-doped carbon ring structure could effectively confine SeS 2 in the form of small molecules and regulate its electronic structure. The superior sodium/potassium storage performance of the OC/SeS 2 composite electrodes stems from their rational chemical structure design, including high electrical conductivity of the N-doped organic carbon network and chemical binding with SeS 2 molecules. As a result, the OC/SeS 2 cathode delivers a reversible capacity of 416 mAh g −1 after 700 cycles for sodium-ion batteries and 216 mAh g −1 after 500 cycles for potassium-ion batteries at 0.5 A g −1 , respectively. These findings could open a new window to develop selenium sulfide cathode for metal−sulfur/selenium batteries.

Electrochemical Insights, Developing Strategies, and Perspectives toward Advanced Potassium–Sulfur Batteries

“…Reproduced with permission. [ 28 ] Copyright 2019, ACS Publishing Group. k) Rate performance comparison of Se@NCNFs, SeS 2 @NCNFs, and S@NCNFs.…”

“…The former undergoes a more advanced development originated from a series of practical breakthroughs, such as the general recognition of the discharge products, the optimization of sulfur cathodes to address the low conductivity, and the successful modification of electrolyte or separator to retard the polysulfide dissolution. [24,26,42] Specifically, the performances of K-S batteries have not been satisfactory because of following four main limitations: [25,[27][28][29] 1) the infamous shuttle effect of soluble potassium-polysulfide restrict full reduction/oxidation in the charge/discharge process, which results in a poor coulombic efficiency and an obvious capacity decay; 2) the insulating nature of sulfur results in a limited utilization of theoretical capacity; 3) the large ionic radius of K + (1.38 Å vs Li + , 0.76 Å) makes it difficult to insert/extract rapidly in the carbon-based anodes, causing slow diffusion dynamics; meanwhile, the density difference of charge/discharge products causes volume exploding of electrode, deteriorating electrochemical reversibility; 4) the high reactivity K-metal anode leads to unstable solid electrolyte interphase (SEI) and dendrite growth.…”

“…l') Reproduced with permission. [ 28 ] Copyright 2019, ACS Publishing Group. m') Reproduced with permission.…”

Calixarene‐Functionalized Porous Carbon Aerogels for Polysulfide Capture: Cathodes for High Performance Lithium‐Sulfur Batteries

“…The spectra of C 1s ( Figure 6c) has three peaks at 288.3, 286.5 and 284.7 eV and they are attributed to C=O, CÀ C and CÀ O bonds, respectively. [33] Furthermore, [34] Figure 6d presents two peaks at 165.2 and 163.9 eV relating to S 2p 1/2 and S 2p 3/2 and indicates sublimed sulfur successfully penetrating in SACA. [35] The adsorption abilities of CA, ACA and SACA to polysulfide by UV/Vis spectroscopy are shown in Figure 7.…”

Dual Play of Chitin‐Derived N‐Doped Carbon Nanosheets Enabling High‐Performance Na‐SeS2 Half/Full Cells

“…After that, many works have investigated remarkable electrochemical performance for Li‐Se x S y batteries, and the relevant mechanism are proposed by various of characterization techniques . Nevertheless, only a few literatures about Na‐Se x S y are reported, and deeper understanding of the mechanism during charge and discharge still remains unclear, even though it seems more necessary to explore the application of Se x S y in Na storage to improve the poor reactivity between metal Na and active materials. Yu and co‐workers have proposed a simple method to heat S 0.6 Se 0.4 and PAN nanofibers, affording a flexible S 0.6 Se 0.4 @carbon nanofibers film which has demonstrated ultra‐long cycle performance with a reversible capacity of 346 mAh g −1 maintained after 1000 cycles .…”