11 Lithium-Ion Battery—3D Micro-/Nano-Structuring, Modification …
337
analytic tool should act as feedback control between electrochemical performance
and the generated laser-assisted 3D architectures. Laser-induced breakdown spectroscopy (LIBS) seems to be a powerful item and was therefore intensively applied to
characterize 3D structures on thick film electrodes post-mortem (after battery tests).
LIBS is an analysis method which offers the possibility to characterize the elemental
composition very fast [88] and it is capable of performing direct 3D analysis with
micrometric [89] or nanometric resolution [90]. Only one single laser pulse under
ambient air is required in order to generate a laser-induced plasma and the achieved
chemical information can be directly correlated with a local State-of-Health (SOH).
Characterization methods such as bulk analysis, depth profiling, elemental mapping
as well as layer-by-layer analysis can be performed at atmospheric pressure condition
[91, 92]. In the field of lithium-ion batteries, LIBS is a rather new approach in order to
obtain post-mortem critical information on surface phenomena that define and control
the performance of Li-based battery systems. As a powerful analytical tool, LIBS
can be used for an entire analysis of large-areal 3D battery sheets. Besides a large
area surface characterization also an elemental mapping of the complete electrode
bulk material down to the current collector can be realized. Post-lithium concepts,
3D battery concepts, and thick film electrode concepts can be investigated in order to
achieve advanced high energy and high power batteries. This new research field has
great potential to study aging effects as a function of electrochemical performance,
(e.g., lifetime, cycle retention), cycle parameters, and 3D-concept parameter (aspect
ratio, active surface area, porosity). Finally, LIBS is a flexible analytical method for
measuring of chemical patterns that are induced by 3D topographies, degradation,
or aging processes.
In recent research studies, it could be shown for the first time that LIBS can
be successfully applied to analyze chemical compositions along complete electrode
surfaces of cycled or uncycled cells. Element mapping and element depth-profiling
were applied for characterizing the electrode as function of SoH and cell architecture [56, 93–95]. This new approach for cell characterization requires a specialized
calibration procedure based on electrochemical titration in order to produce NMC
samples with defined lithium amount [55]. In the current chapter we describe the
manufacturing of 3D NMC electrodes, their electrochemical cycling behavior, and
subsequent post-mortem elemental characterization by using LIBS.
11.5.1 Manufacturing Route for 3D Electrodes
The fabrication of 3D electrodes can be divided into four main processing steps
(Fig. 11.21a-d): (a) slurry preparation, (b) coating/drying, (c) calendering, and (d)
ultrashort laser structuring.
The cathode slurry was prepared by mixing 90 wt% of lithium nickel manganese
cobalt oxide (LiMeO 2 , Me = Ni:Mn:Co = 1:1:1), 5 wt% of conductive additive
(TIMCAL SUPER C65) and 5 wt% of polyvinylidene fluoride (PVDF) binder.
N-Methyl-2-pyrrolidone (NMP) was used as solvent. Additionally, the slurry was
337
analytic tool should act as feedback control between electrochemical performance
and the generated laser-assisted 3D architectures. Laser-induced breakdown spectroscopy (LIBS) seems to be a powerful item and was therefore intensively applied to
characterize 3D structures on thick film electrodes post-mortem (after battery tests).
LIBS is an analysis method which offers the possibility to characterize the elemental
composition very fast [88] and it is capable of performing direct 3D analysis with
micrometric [89] or nanometric resolution [90]. Only one single laser pulse under
ambient air is required in order to generate a laser-induced plasma and the achieved
chemical information can be directly correlated with a local State-of-Health (SOH).
Characterization methods such as bulk analysis, depth profiling, elemental mapping
as well as layer-by-layer analysis can be performed at atmospheric pressure condition
[91, 92]. In the field of lithium-ion batteries, LIBS is a rather new approach in order to
obtain post-mortem critical information on surface phenomena that define and control
the performance of Li-based battery systems. As a powerful analytical tool, LIBS
can be used for an entire analysis of large-areal 3D battery sheets. Besides a large
area surface characterization also an elemental mapping of the complete electrode
bulk material down to the current collector can be realized. Post-lithium concepts,
3D battery concepts, and thick film electrode concepts can be investigated in order to
achieve advanced high energy and high power batteries. This new research field has
great potential to study aging effects as a function of electrochemical performance,
(e.g., lifetime, cycle retention), cycle parameters, and 3D-concept parameter (aspect
ratio, active surface area, porosity). Finally, LIBS is a flexible analytical method for
measuring of chemical patterns that are induced by 3D topographies, degradation,
or aging processes.
In recent research studies, it could be shown for the first time that LIBS can
be successfully applied to analyze chemical compositions along complete electrode
surfaces of cycled or uncycled cells. Element mapping and element depth-profiling
were applied for characterizing the electrode as function of SoH and cell architecture [56, 93–95]. This new approach for cell characterization requires a specialized
calibration procedure based on electrochemical titration in order to produce NMC
samples with defined lithium amount [55]. In the current chapter we describe the
manufacturing of 3D NMC electrodes, their electrochemical cycling behavior, and
subsequent post-mortem elemental characterization by using LIBS.
11.5.1 Manufacturing Route for 3D Electrodes
The fabrication of 3D electrodes can be divided into four main processing steps
(Fig. 11.21a-d): (a) slurry preparation, (b) coating/drying, (c) calendering, and (d)
ultrashort laser structuring.
The cathode slurry was prepared by mixing 90 wt% of lithium nickel manganese
cobalt oxide (LiMeO 2 , Me = Ni:Mn:Co = 1:1:1), 5 wt% of conductive additive
(TIMCAL SUPER C65) and 5 wt% of polyvinylidene fluoride (PVDF) binder.
N-Methyl-2-pyrrolidone (NMP) was used as solvent. Additionally, the slurry was