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Design Considerations for Fast Charging Lithium Ion Cells for NMC/MCMB Electrode Pairs

by William Yourey, Yanbao Fu, Ning Li, Vincent Battaglia and Wei Tong

Batteries 2021, 7(1), 4; https://doi.org/10.3390/batteries7010004 - 5 Jan 2021

Cited by 8 | Viewed by 6079

Lithium ion cells that can be quickly charged are of critical importance for the continued and accelerated penetration of electric vehicles (EV) into the consumer market. Considering this, the U.S. Department of Energy (DOE) has set a cell recharge time goal of 10–15 min. The following study provides an investigation into the effect of cell design, specifically negative to positive matching ratio (1.2:1 vs. 1.7:1) on fast charging performance. By using specific charging procedures based on negative electrode performance, as opposed to the industrial standard constant current constant voltage procedures, we show that the cells with a higher N:P ratio can be charged to ~16% higher capacity in the ten-minute time frame. Cells with a higher N:P ratio also show similar cycle life performance to those with a conventional N:P ratio, despite the fact that these cells experience a much higher irreversible capacity loss, leading to a lower reversible specific capacity. Full article

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11 pages, 2684 KiB

Open AccessArticle

Highly Graphitized Carbon Coating on SiO with a π–π Stacking Precursor Polymer for High Performance Lithium-Ion Batteries

by Shan Fang, Ning Li, Tianyue Zheng, Yanbao Fu, Xiangyun Song, Ting Zhang, Shaopeng Li, Bin Wang, Xiaogang Zhang and Gao Liu

Polymers 2018, 10(6), 610; https://doi.org/10.3390/polym10060610 - 4 Jun 2018

Cited by 17 | Viewed by 6909

Abstract

A highly graphitized carbon on a silicon monoxide (SiO) surface coating at low temperature, based on polymer precursor π–π stacking, was developed. A novel conductive and electrochemically stable carbon coating was rationally designed to modify the SiO anode materials by controlling the sintering of a conductive polymer, a pyrene-based homopolymer poly (1-pyrenemethyl methacrylate; PPy), which achieved high graphitization of the carbon layers at a low temperature and avoided silicon carbide formation and possible SiO material transformation. When evaluated as the anode of a lithium-ion battery (LIB), the carbon-coated SiO composite delivered a high discharge capacity of 2058.6 mAh/g at 0.05 C of the first formation cycle with an initial Coulombic efficiency (ICE) of 62.2%. After 50 cycles at 0.1 C, this electrode capacity was 1090.2 mAh/g (~82% capacity retention, relative to the capacity of the second cycle at 0.1 °C rate), and a specific capacity of 514.7 mAh/g was attained at 0.3 C after 500 cycles. Furthermore, the coin-type full cell composed of the carbon coated SiO composite anode and the Li[Ni_0.5Co_0.2Mn_0.3O₂] cathode attained excellent cycling performance. The results show the potential applications for using a π–π stacking polymer precursor to generate a highly graphitize coating for next-generation high-energy-density LIBs. Full article

(This article belongs to the Special Issue π-Stacked Polymers)

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