Chemical Strain of Graphite-Based Anode during Lithiation and Delithiation at Various Temperatures

Abstract

Electrochemical lithiation/delithiation of electrodes induces chemical strain cycling that causes fatigue and other harmful influences on lithium-ion batteries. In this work, a homemade in situ measurement device was used to characterize simultaneously chemical strain and nominal state of charge, especially residual chemical strain and residual nominal state of charge, in graphite-based electrodes at various temperatures. The measurements indicate that raising the testing temperature from 20°C to 60°C decreases the chemical strain at the same nominal state of charge during cycling, while residual chemical strain and residual nominal state of charge increase with the increase of temperature. Furthermore, a novel electrochemical-mechanical model is developed to evaluate quantitatively the chemical strain caused by a solid electrolyte interface (SEI) and the partial molar volume of Li in the SEI at different temperatures. The present study will definitely stimulate future investigations on the electro-chemo-mechanics coupling behaviors in lithium-ion batteries.

Highly Reversible Lithiation of Additive Free T‐Nb2O5 for a Quarter of a Million Cycles

“…The uncycled electrodes had an average capacity of 196 ± 5 mAh g −1 corresponding to Li 1.94 Nb 2 O 5 which is close to the theoretical capacity and is in line with similar reports. [ 26,31,40,42,47–49 ] Also apparent in this plot is that most of the capacity is stored between 1.2–2.0 V versus Li/Li + , so it is expected that most of the SOC‐related degradation would occur between these voltages. From these characterizations, the as‐prepared electrodes were consistent with uniform nanostructured T‐Nb 2 O 5 with typical electrochemical characteristics.…”

“…Lower extents of lithiation are a pragmatic approach to extending cycling longevity and are known to improve cycling stability in diverse intercalation electrodes by reducing the total amount of strain ("breathing") upon cycling. [48][49][50] This strategy is rational from an economic perspective if the reduced capacity is more than offset by increases in longevity. Diagnostic ("Full-Slow") CV measurements are shown before and after 0.25 million cycles of rapid Full-t0 cycling (Figure 2c).…”

Chemical Strain Analysis of the VO2 Cathode for Zn-Ion Batteries at Different Temperatures

“…A homemade in situ strain test system (Figure S1) is composed of a CCD camera, an LED light source, and a homemade electrochemical cell. 28 The homemade cell features a transparent quartz window at the front to allow for the passage of light and the capture of optical images of the electrode. The freestanding electrode is welded to the stainless steel substrate to form a cantilever electrode.…”

Fundamentals, status and challenges of direct recycling technologies for lithium ion batteries

“…19b, a monotonic increase and decrease in anisotropic tensile strain can be observed during lithiation/delithiation. 240 At the end of delithiation, a residual tensile strain still exists, indicating the occurrence of an irreversible electrochemical process. Although the structural framework of graphite is relatively stable, after long-term repeated stretching and contraction and the accumulation of irreversible reactions, some structural defects and even layer peel off occur, resulting in the decay of the capacity of graphite.…”

“…Fig. 19 (a) In situ NPD pattern of graphite anode materials in an NCM523/graphite full cell, 239 Copyright 2022, Elsevier; (b) strain contours of a freestanding graphite-based composite electrode at different nominal SOCs in the first cycle, 240 Copyright 2021, the author(s); (c) schematic of the interphase formation chemistry in a graphite anode during the early lithiation, 242 Copyright 2019, Springer Nature; (d) optical photo of metallic Li plating on graphite electrode, 243 Copyright 2020, PNAS; (e) TOF-SIMS depth profiles of selected ion fragments on the surface of a cycled graphite electrode, 245 Copyright 2022, Wiley.…”