How Do Reactions at the Anode/Electrolyte Interface Determine the Cathode Performance in Lithium-Ion Batteries?

Abstract

Today, it is common knowledge, that materials science in the field of electrochemical energy storage has to follow a system approach as the interactions between active materials, electrolyte, separator and various inactive materials (binder, current collector, conductive fillers, cell-housing, etc.) which are of similar or even higher importance than the properties and performance parameters of the individual materials only. In particular, for lithium-ion batteries, it is widely accepted that the electrolyte interacts and reacts with the electrodes. Here, we report how reactions at a graphite anode (involving electrolyte decomposition and solid electrolyte interphase (SEI) formation), affect the performance of a LiCoO2 (LCO) cathode and the full lithium-ion cell during cycling. We discuss effects of the SEI-forming electrolyte additive vinylene carbonate (VC) and the influence of graphite anodes with different surface areas on the cycling stability, end of charge (EOC) and end of discharge (EOD) potentials of the LCO cathode. We will thus elucidate the failure mechanism of LCO/graphite cells by showing that the formation and growth of SEI on the anode, resistance increase in the cathode, electrode and electrolyte degradation in general, as well as capacity and power fade of the lithium ion cell are in fact strongly interrelated processes.

Electrode Behavior RE-Visited: Monitoring Potential Windows, Capacity Loss, and Impedance Changes in Li1.03(Ni0.5Co0.2Mn0.3)0.97O2/Silicon-Graphite Full Cells

“…An increase in upper cutoff potential of a LiCoO 2 electrode when cycled versus graphite was reported by Krueger et al in a reference electrode study. 33 Similarly, Beattie et al recently demonstrated the evolution to higher cycling potentials of both electrodes in a LiNi 0.8 Co 0.15 Al 0.05 O 2 /silicon couple. 34 State-of-the-art layered oxides are not cycled over their entire theoretical capacity span both in order to stay within the stability windows of the electrolyte and to avoid irreversible structural changes detrimental to their performance.…”

Pre-Lithiation Strategies for Rechargeable Energy Storage Technologies: Concepts, Promises and Challenges

“…Likely, because there are several problems to overcome before it is possible to incorporate this process into a commercial battery cell manufacturing process, for example the evaporation of the electrolyte solvents, the high reactivity of the Li metal foil or the problem of high surface area lithium (HSAL) formation. However, Kim et al also presented that the external shorting with Li metal enables a delicate control on the degree of pre-lithiation (Figure 4), which is of high importance, especially with a focus on anode/cathode capacity balancing [28,56], SEI formation and the prevention of lithium metal plating at the negative electrode [30]. They conceived a scalable roll-to-roll process based on external shorting with Li metal foil for the pre-lithiation of carbon-coated silicon monoxide (c-SiO x ; x ≈ 1).…”

Novel application of differential thermal voltammetry as an in-depth state-of-health diagnosis method for lithium-ion batteries

“…The rate of degradation depends on various storage and operating conditions such as voltage, current, temperature and pressure [6,12]. These can all lead to various degradation mechanisms in different parts of the cell such as solid electrolyte interphase (SEI) layer formation at the negative electrode or metal dissolution at the positive electrode.…”