Oxygen Containing Carbon Materials for High Capacity and Fast Chargeable Anode Materials of Lithium Ion Batteries

Abstract

The lithium-ion battery is the most promising energy storage devices for variety of applications from portable electronics to electric vehicles because of its high energy density, power density and cycle life. However, the upcoming boom for artificial intelligence (AI) assisted transportations, Internet of Things (IoT) or potential wireless financial technologies may require batteries with much higher energy density and fast chargeable capability. Silicon and silicon monoxide have been extensive investigated for high capacity anode for more than 10 years. However, they are still hard to be used in real practice because of large volumetric expansion, poor cycle life, and bad rate capability. On the other hand, graphite is the most popular commercialized anode material for Li-ion battery because of its excellent coulombic efficiency, long cycle life, low cost and ease of processing. However, the limited theoretical capacity (372 mAh/g) and small interlayer spaces (0.335 nm) made it difficult to be used in the application of Li-ion batteries with higher energy density and fast chargeable Li-ion batteries (Fig.1a). In this study, we have introduced a novel Graphene-Like-Graphite (GLG) anode material to be used in Li-ion batteries with higher capacity and good rate capability. According to the Li-NMR study, lithium ions can intercalate into graphene layers with oxygen at 0-1.2V (vs Li) with non-stage phenomenon and delivered a capacity more than 372mAh/g. Meanwhile, at a higher potential range from 1.2 to 2V (vs Li), lithium ions continuous react with oxygen containing functional groups reversibly on the basal plane of each graphene layer. As a result, the GLG could have an initial discharge capacity up to 608mAh/g which is much larger than conventional graphite (372mAh/g). It was investigated that the higher oxygen content offers a higher reversible capacity over 1.2V (vs Li) discharge. Atom resolution STEM is also carried out for the characterization of single layer graphene of the GLG. It was learned that the GLG graphene layer has pore structure with the size less than 2nm, moreover the oxygen containing functional groups were attached on both basal plane and pores` s edge. The GLG was also characterized with NCM111 cathode for full-cell rate capability and cyclability. The cell charged to 60% of the capacity up to 6C (10min) charge with 103wh/kg cell design, while have good cycle ability. XPS, HAXPES, C-NMR were also used for the characterization of the GLG materials. Finally, a structure model was proposed for the next generation high rate, high capacity carbon based anode materials. Figure 1