China\u27s hold on the lithium-ion battery supply chain: Prospects for competitive growth and sovereign control

Battery production for electric vehicles (EVs) necessitates a supply chain capable of supporting the exploitation of a variety of raw materials. Lithium, nickel, manganese, and cobalt are of particular significance for the dominant lithium-ion battery (LIB) technology, primarily relying on lithium iron phosphate (LFP) and lithium nickel manganese cobalt oxide (NMC) cathodes. Geographically, the global supply is heavily reliant on China with competition expected to intensify. In light of this, the questions of how global competition manifests at the company level and whether regions capture their share of the supply chain through domestic companies remain unanswered. These are addressed by analyzing the companies behind each supply chain sector and the respective raw materials. The results demonstrate that China, Europe, and the United States of America (USA) exhibit the most pronounced ownership across the supply chain, acquiring the largest foreign shares in the mining sector. Overall, China leads in a total of eleven out of the 12 investigated sectors, with its peak for LFP production at above 98 %. This preeminence, coupled with the substantial output of South Korea, Europe, and Japan in NMC production, the latter represents a viable target for mitigating supply chain vulnerabilities and attaining greater growth and sovereignty

Characterizing surface finish and fatigue behavior in binder-jet 3D-printed nickel-based superalloy 625

In this study, the fatigue properties of binder-jet 3D-printed nickel-base superalloy 625 were evaluated. Standard fatigue specimens were printed and sintered, then half of the samples were mechanically ground, while the other half were left in their as-sintered state. They were then characterized using micro-computed x-ray tomography, metallographic sample examination, and optical and stylus profilometry for surface topography. The micro-computed tomography observations showed that density of the as-printed sample was ~50%, while the sintered sample neared full densification (98.9 ± 0.3%) upon sintering at 1285 °C for 4 h in a vacuum atmosphere. The metallographic examination showed equiaxed grains. The roughness of the as-sintered samples was significant with an RMS roughness of Rq = 1.39 ± 0.20 μm as measured over a line-scan of 5 mm, but this was reduced to Rq = 0.47 ± 0.02 μm after mechanical grinding. All samples were tested to failure in fatigue, under fully-reversed tension-compression conditions. While the as-sintered samples showed poor fatigue properties compared to prior reports on cast and milled parts, the ground samples showed superior performance. Scanning electron microscopy observation was conducted on the fractured surfaces and showed that the samples underwent transgranular crack initiation, followed by intergranular crack growth and final failure. In the mechanically ground sample, hardness increased nearly two-fold up to 75 µm beneath the sample’s surface and X-ray diffraction indicated an in-plane compressive stress, grain refinement, and micro-strain on the mechanically ground sample. The reduced roughness, surface hardening, and compressive stress resulted in increased fatigue life of the binder-jetted alloy 625