Analysis of geometric and electrochemical characteristics of lithium cobalt oxide electrode with different packing densities

Abstract

To investigate geometric and electrochemical characteristics of Li ion battery electrode with different packing densities, lithium cobalt oxide (LiCoO 2 ) cathode electrodes were fabricated from a 94:3:3 (wt%) mixture of LiCoO 2 , polymeric binder, and super-P carbon black and calendered to different densities. A synchrotron X-ray nano-computed tomography system with a spatial resolution of 58.2 nm at the Advanced Photon Source of the Argonne National Laboratory was employed to obtain three dimensional morphology data of the electrodes. The morphology data were quantitatively analyzed to characterize their geometric properties, such as porosity, tortuosity, specific surface area, and pore size distribution. The geometric and electrochemical analysis reveal that high packing density electrodes have smaller average pore size and narrower pore size distribution, which improves the electrical contact between carbon-binder matrix and LiCoO 2 particles. The better contact improves the capacity and rate capability by reducing the possibility of electrically isolated LiCoO 2 particles and increasing the electrochemically active area. The results show that increase of packing density results in higher tortuosity, but electrochemically active area is more crucial to cell performance than tortuosity at up to 3.6 g/cm 3 packing density and 4 C rate.

Three-Dimensional Reconstruction and Analysis of All-Solid Li-Ion Battery Electrode Using Synchrotron Transmission X-ray Microscopy Tomography

“…Figure 1e shows a representative reconstructed 2D slice image of 700 psi all-solid electrode. Compared to our previous X-ray CT images of liquid electrolyte electrodes, such as LCO and NMC [27][28] , the allsolid electrode has three phases to be distinguished. As shown in Figure 1e, the white phase is NMC, the gray phase is LTAP and the black phase includes both pore and 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 8 super-P carbon.…”

Reticulate Dual‐Nanowire Aerogel for Multifunctional Applications: a High‐Performance Strain Sensor and a High Areal Capacity Rechargeable Anode

“…However, the mass specific capacity is affected by the high mass loading. The higher mass loadings in our electrodes were obtained via an intense densification approach that led to an enhanced CNT connection and larger specific surface areas (Figure S16a, Supporting Information) . They enhanced the conductivity of the electrodes, facilitated the charge transfer process, provided more active sites for electrochemical reactions and a decreased R ct value.…”

Analysis of the 3D microstructure of experimental cathode films for lithium‐ion batteries under increasing compaction

“…Both characteristics provide valuable information concerning the geometry of transportation paths of lithium‐ions since the morphology of the pore phase influences the electrochemical performance of lithium‐ion batteries, see Lim et al . (). Further details regarding c‐PSD and MIP‐PSD can be found in Münch & Holzer () and Holzer et al .…”

“…It is important to point out that c-PSD as well as MIP-PSD has been normalized by the total volume of the pore phase in order to obtain comparable results. Both characteristics provide valuable information concerning the geometry of transportation paths of lithiumions since the morphology of the pore phase influences the electrochemical performance of lithium-ion batteries, see Lim et al (2016). Further details regarding c-PSD and MIP-PSD can be found in Münch & Holzer (2008) and Holzer et al (2013b).…”