Damage Evaluation in Lithium Cobalt Oxide/Carbon Electrodes of Secondary Battery by Acoustic Emission Monitoring

Abstract

Acoustic Emission (AE) technique was employed for evaluating charge/discharge damage in a lithium-ion battery. A coin-type battery of lithium cobalt oxide/carbon electrodes was used for acoustic monitoring during accelerated charge/discharge cycle test. A number of AE signals were successfully detected during charge/discharge. Microstructural observation of the electrodes after the cycle test revealed mechanical damage such as micro-cracking of the cathode and chemical damage such as solid electrolyte interphase (SEI) layer formed on the anode. The detected AE signals were classified into two distinct types (i.e., type 1 and type 2) based on the AE waveform parameters (i.e., duration and amplitude). The main frequency component of the type 1 signal with short duration and high amplitude was in the range of 121160 kHz, whereas the frequency of type 2 signals with long duration and low amplitude was between 81 and 120 kHz. Active AE source of type 1 and type 2 signal was attributed to micro-cracking in cathode and gas bubble accompanied by SEI layer formation on anode, respectively. These results demonstrate the feasibility of the AE technique for the evaluation of charge/discharge degradation of secondary battery.

The effect of electrochemical cycling on the strength of LiCoO2

“…For example, experiments on LiCoO 2 observed a somewhat steady number of acoustic events during cycling, while other experiments measured a large number of acoustic events in the first cycle followed by a much lower rate in later cycles . Other work on this system found that a bimodal distribution in the acoustic event frequency versus amplitude, and attributed some events to cracking and other events to gas bubble nucleation during solid electrolyte interphase formation . The occurrence of cracking events was somewhat constant with cycle number in their experiments, while bubble nucleation accounted for the majority of the first‐cycle acoustic events.…”

“…Several studies have utilized acoustic emission to understand the evolution of damage in these materials, but the results and conclusions vary. For example, experiments on LiCoO 2 observed a somewhat steady number of acoustic events during cycling, while other experiments measured a large number of acoustic events in the first cycle followed by a much lower rate in later cycles . Other work on this system found that a bimodal distribution in the acoustic event frequency versus amplitude, and attributed some events to cracking and other events to gas bubble nucleation during solid electrolyte interphase formation .…”

“…The occurrence of cracking events was somewhat constant with cycle number in their experiments, while bubble nucleation accounted for the majority of the first‐cycle acoustic events. The occurrence of cracking in LiCoO 2 depends on system variables such as particle size and cycling rate, as well as materials properties such as strength and fracture toughness . The main question addressed herein is whether cycling at a constant average rate and with a constant particle size distribution exhibits cycle number sensitive cracking because the process is stochastic and caused by factors such as local variation in reaction rate, or if instead the fundamental mechanical properties of the system evolve during cycling.…”

The Sound of Batteries: An Operando Acoustic Emission Study of the LiNiO2 Cathode in Li–Ion Cells

“…The same applies to the AE 2 hits, which according to literature lie at the border of acoustic activity between gassing and cracking. [40,42,59,62] Because the acoustic activity in the frequency range of AE 2 also decreased to a minor fraction after the initial cycle, we assign it to cSEI formation. Similar results that contradict the classical assignment of AE signals to gassing were observed in the investigation of silicon anodes and deposition of calcium carbonate and zinc phosphate.…”

“…For instance, Kircheva et al used AE to probe the solid-electrolyte interphase (SEI) formation and lithium intercalation into the bulk of graphite electrodes. [39] Moreover, Choe et al analyzed damage mechanisms in lithium cobalt oxide (LiCoO 2 , LCO) and graphite electrodes by classifying AE signals into distinct types, [40] and Villevieille et al investigated conversion-type reactions in NiSb 2 electrodes. [41] Other LIB materials, such as silicon and metal hydrides, have also been studied; yet, Ni-rich layered oxide cathode materials have not been examined to date.…”