Anode material for lithium-sulfur batteries and preparation method of anode material

Abstract

The invention relates to an anode material for lithium-sulfur batteries and a preparation method of the anode material. The anode material comprises a current collector, an anode active substance spread on the current collector, a conductive agent and a binding agent, wherein the current collector is aluminium foil, the conductive agent is acetylene black, and the binding agent is polyvinylidene fluoride; the anode material is characterized in that the anode active substance is sulfur source TMTD-t-T decomposed from TMTD (tetramethyl thiuram disulfide) at different times t and different temperatures T, wherein t is equal to 12 or 24 h, T is equal to 120, 140, 160 or 180 DEG C; the anode material is prepared in such a way that the TMTD-t-T, the conductive agent and the binding agent are homogeneously mixed and dissolved in N-methyl-2-pyrrolidone to form paste, the paste is spread on the surface of the current collector, and vacuum drying is performed; through introduction of the organic sulfur source TMTD, the electrochemical reversibility and circulating stability of the lithium-sulfur batteries are remarkably improved.

Description

[0001] technical field [0002] The invention relates to a positive pole piece for a lithium-sulfur battery with an organic sulfur source TMTD as an active material and a preparation method thereof, belonging to the field of electrochemical batteries. Background technique [0003] With the rapid development of portable electronic devices, it is imminent to develop new secondary battery systems with higher energy density. Lithium-sulfur battery cathode material sulfur undergoes multiple electron transfer reaction: S 8 + 16e -1 + 16Li + = 8Li 2 S. If sulfur is completely converted to Li 2 S, the theoretical specific capacity of sulfur is as high as 1675 mAh / g, and the open circuit voltage is 2.2 V ( vs. Li / Li + ), so that its theoretical energy density is 2600 Wh / kg, which is much larger than the commercial secondary batteries used at this stage. In recent years, lithium-sulfur batteries with high capacity and high energy density have become one of the research...

AI Technical Summary

Problems solved by technology

[0004] However, the practical application of lithium-sulfur batteries also faces many problems. First, elemental sulfur is an insulator of electrons and ions (5×10 -30 S / cm); secondly, lithium polysulfide, an intermediate product of sulfur electrode charge and discharge, is easily soluble in organic electrolyte

These soluble lithium polysulfides will diffuse to the surface of the lithium negative electrode through the electrolyte, react with lithium to form low-priced lithium polysulfides, and then diffuse back to the sulfur positive electrode, causing corrosion of the lithium negative electrode and loss of active materials.

The occurrence of this "shuttle effect" directly reduces the cycle stability of sulfur electrodes and leads to low Coulomb effect, which seriously restricts the practical application of lithium-sulfur batteries.

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