Lithium metal battery negative electrode current collector for inhibiting dendritic crystal growth and modification method thereof

Abstract

The invention discloses a lithium metal battery negative electrode current collector capable of inhibiting dendritic crystal growth and a modification method thereof, belongs to the field of lithium battery negative electrode dendritic crystal growth inhibition, and aims to reduce the generation of lithium dendrites and the formation of dead lithium and improve the coulombic efficiency and the cycle life of a lithium metal negative electrode by performing corresponding treatment on a Cu current collector. The surface of the current collector is modified with a layer of PES film through a spin-coating method, the PES film contains a large number of polar functional groups O = S = O, and in the lithium deposition process, the polar functional groups can induce uniform nucleation of lithium ions, so that growth of lithium dendrites is inhibited; meanwhile, wettability of an electrode interface is improved, impedance of a negative electrode and an electrolyte solid-liquid phase interface is reduced, and transmission of interface lithium ions is improved; and the PES high polymer covers the copper foil, so that the direct contact between the electrode and the electrolyte can be prevented, and the consumption of the electrolyte in the circulation process is prevented.

Description

technical field [0001] The invention belongs to the field of inhibiting the growth of dendrites of negative electrodes of lithium batteries, and in particular relates to a current collector of negative electrodes of lithium metal batteries capable of inhibiting the growth of dendrites and a modification method thereof. Background technique [0002] With the rapid development and application of portable charging and discharging equipment, in mobile energy storage equipment, a long charging interval is a new requirement for high energy density batteries. Lithium metal has a very high theoretical specific capacity (3860 mAh g -1 ), which is more than 10 times that of carbon materials; a new generation of rechargeable batteries with metal lithium as the negative electrode has important research value and broad application prospects. The application of lithium metal batteries with high energy density, lithium air, and lithium oxygen batteries must be based on a mature lithium me...

AI Technical Summary

Problems solved by technology

[0003] The current main problem of the lithium metal negative electrode is that the electrons obtained by lithium ions under the reduction potential of lithium are transformed from ion state to metal state and deposited on the current collector. Due to the intrinsic characteristics of lithium metal and uneven distribution of current density, dendritic lithium metal is formed. — "Dendrite Lithium"

Lithium dendrites tend to break and form "dead lithium" during multiple deposition / stripping cycles, resulting in the loss of lithium metal anode active materials and electrolyte, resulting in a sharp decrease in reversible capacity and a rapid decline in Coulombic efficiency.

At the same time, the dendrites deep in the electrolyte tend to reduce the strength of the electrolyte interface film (SEI) on the surface of the lithium metal negative electrode, affecting the stability of the battery structure and greatly shortening the service life of the battery.

Among the current methods of inhibiting lithium dendrites, the regulation of electrolyte composition and the use of electrolyte additives are the most convenient solutions. However, in the actual operation of the battery, irreversible chemical reactions will continue to occur in the additives, and the additive effect will continue to decline.

The high Young's modulus of solid electrolytes can inhibit the growth of lithium dendrites, which can effectively improve the safety performance of lithium negative electrodes. However, the ionic conductivity of solid electrolytes is much lower than that of liquid electrolytes, and the battery impedance increases significantly, resulting in low battery efficiency.

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