Study on Li Metal Deposition, SEI Formation on Anodes and Cathode Potential Change during the Pre-Lithiation Process in a Cell Prepared with Laminated Porous Anodes and Cathodes

Abstract

The pre-doping of Li + ions (pre-lithiation) in graphite anodes, which is needed to improve the initial charging/discharging efficiency of lithium ion batteries, was examined from the viewpoints of lithium metal deposition, surface electrolyte interface (SEI) formation and electrode potential changes in the cathode during the pre-lithiation. Using a cell composed of pre-laminated, through-holed anodes and cathodes, the anodes were pre-lithiated with the perpendicular pre-doping method, as explained in this work, which can effectively enhance the pre-lithiation process in laminated cells. In the pre-lithiation system, Li deposition was not observed on the anode surfaces during pre-lithiation, and the thickness of the SEI layers formed on the anodes did not increase. Moreover, the SEI layer has the same composition as that formed by the electrochemical lithiation (charging) process, even when the pre-lithiation of the anodes is accelerated by throughholes formed on the anode and cathode electrodes. In addition, the electrode potential of cathodes inserted between pre-lithiated anodes does not change during the pre-lithiation process, and the capacity of the cathodes does not degrade upon pre-lithiation. The perpendicular pre-doping method examined in this study is found to be applicable to the production process of lithium ion batteries with high charging/discharging efficiency.

A perspective on the evolution and journey of different types of lithium-ion capacitors: mechanisms, energy-power balance, applicability, and commercialization

“…To avoid the reassembly step, during the fabrication of the LIC full cell, an auxiliary Li metal is pre-embedded into the system, and the procedure is completed by external short-circuiting between the anode and Li electrode until the complete consumption of auxiliary lithium. 112,113 The important factors to be mentioned are: (1) the amount of pre-embedded lithium ions determines the level of pre-lithiation; (2) pre-lithiation rate and duration depend on the external load resistance. (3) Use of a porous current collector is necessary.…”

“…These Li + ions diffuse from one electrode to the other electrode through the porous current collector. 114 Its advantages are: (1) it eliminates the reassembly process. In situ mechanical short circuit.…”

“…These Li + ions diffuse from one electrode to the other electrode through the porous current collector. 114…”

A Review: Pre‐lithiation Strategies Based on Cathode Sacrificial Lithium Salts for Lithium‐Ion Capacitors

“…Reproduced with permission. [ 54–66 ] Copyright 2022 IOP Publishing. Copyright The Royal Society of Chemistry 2017.…”

Insights into Chemical Prelithiation of SiOx/Graphite Composite Anodes through Scanning Electron Microscope Imaging

“…Anode prelithiation consists of mechanical prelithiation, electrochemical prelithiation, , and chemical prelithiation. , Electrochemical prelithiation is a safer strategy for electrode prelithiation than the mechanical lithium metal replenishment process due to the unpredictable risks related to lithium powder; however, it is inapplicable for practical use due to its complex operation procedure and electrolyte waste. − Chemical prelithiation is another promising method for anode treatment; the prelithiation reagent provides additional lithium through a redox reaction using organic lithium compounds. ,,, The chemical prelithiation process can also achieve a uniform prelithiation state for all active materials in the electrode, and the degree of prelithiation can be easily regulated with impregnation time. Shen et al applied a lithium naphthalenide reagent to a hard carbon anode and obtained an ICE greater than 95% and a near-complete utilization of electrode-active materials in a full cell.…”