Effect of cathode component on the energy density of lithium–sulfur battery

Preparation and performance of a core–shell carbon/sulfur material for lithium/sulfur battery

“…When the discharge current density is 100 mA g −1 , the upper plateaus is about 2.4 V and the lower one is around 2.1 V, but the obscure cathodic peak at 2.07 V is neglected in discharge curve. The upper plateau is known as the open ring reduction of cyclic S 8 to acyclic Li 2 S 6 , while the lower plateau represents the reductions of S 3 2− /S 3 •− couple, the net reaction is high order polysulfides reduce to low order sulfides, Li 2 S 2 or Li 2 S, as reported previously [18][19][20][21]. Fig.…”

“…10. The simplified equivalent circuit on the upper-right is used to interpret the measured data [19]. It can be seen from the figure that all the Nyquist plots of composites are composed by a semicircle at high frequencies, which is related to the contact resistance and charge transfer resistance, and a short inclined line in low frequency regions, which is due to the ion diffusion within the cathode.…”

Preparation and electrochemical properties of sulfur–acetylene black composites as cathode materials

“…After the sulfur was reduced, the product of lithium polysulfides dissolved in the organic electrolyte; however, the soluble lithium sulfide was well confined due to the strong absorbing ability of the acetylene black [23]. The large interface area, existing between the acetylene black and the lithium polysulfides, offers many electrochemical reaction sites [29]. Moreover, the steric chain-like structure of the acetylene black can provide an excellent conductive network, which is favorable for the electron and charge transfer.…”

A composite material of uniformly dispersed sulfur on reduced graphene oxide: Aqueous one-pot synthesis, characterization and excellent performance as the cathode in rechargeable lithium-sulfur batteries

“…Recently, lithiumsulfur (Li-S) rechargeable batteries have received wide attention, since sulfur possesses a high theoretical capacity of 1675 mA·h/g and a high energy density of 2600 W·h/kg, in addition to the advantages of natural abundance, low cost and environmental friendliness [1][2][3]. However, Li-S rechargeable batteries also suffer from shortcomings [4][5][6][7], such as (i) the electron and ion insulating nature of elemental sulfur, leading to a poor electrical conductivity (5 × 10 -30 S/cm at 25 °C ); (ii) the polysulfides that are generated during the charge/discharge reaction can dissolve in the electrolyte, resulting in low utilization of sulfur active materials and severe capacity fading; and (iii) the polysulfide shuttle phenomenon causes low charge/discharge efficiency and corrosion of the lithium anode. Tremendous efforts have been devoted to overcoming the above problems, including the optimization of new electrolytes [8][9][10][11][12][13], the protection of the lithium anode with a polymer coating [14,15], and the application of conductive matrices and strong adsorbent agents [16][17][18][19][20][21][22][23].…”