An Improved High-rate Discharging Performance of "Unbalanced" LiFePO4 Cathodes with Different LiFePO4 Loadings by a Grid-patterned Micrometer Size-holed Electrode Structuring

Takashi TSUDA, Yuta ISHIHARA, Tatsuya WATANABE, Nobuo ANDO, Takao GUNJI, Naohiko SOMA, Susumu NAKAMURA, Narumi HAYASHI, Takeo OHSAKA, Futoshi MATSUMOTO
2019 Electrochemistry (Tokyo. 1999)  
The degradation of charging/discharging capacities in the rate-performance test of lithium iron phosphate (LFP) cathodes with different loading amounts of an active material on both sides of a current collector (i.e., "unbalanced" LFP/LFP cathodes) in a laminated cell (typically composed of anode/separator/unbalanced cathodes/separator/ anode) was not observed actually at low C-rates (e.g., 0.1 C). However, the rate-performance data obtained at high C-rates (e.g., >5 C) indicated that the
more » ... nce of the loading amounts of an active cathode material on both sides of an Al current collector causes a significant capacity degradation. We have found that it is possible to prevent the capacity degradation observed at high C-rates by holing the unbalanced LFP/LFP cathodes in a micrometer-sized grid-patterned way (the percentages of the holed area are typically several %) using a pico-second pulsed laser: The non-holed unbalanced LFP/LFP cathodes exhibited a considerable capacity degradation at C-rates which are, for example, larger than 5 C, while the holed ones showed no degradation in capacity even at high C-rates (e.g., 5-20 C). Forming micrometer-sized grid-patterned holes in the LFP/LFP cathodes leads to an improved capacity and high-rate performance of their charging/discharging processes.
doi:10.5796/electrochemistry.19-00049 fatcat:6frq7n55ureshitymtott7puye