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Solid-state reactions formed vertical carpets of 2D metal carbides and nitrides on metal substrates. 

Carbonate-based electrolytes are widely used in Li-ion batteries but are limited by a small operating temperature window and poor cycling with silicon-containing graphitic anodes. The lack of non-carbonate electrolyte alternatives such as ether-based electrolytes is due to undesired solvent co-intercalation that occurs with graphitic anodes. Here, we show that fluoroethers are the first class of ether solvents to intrinsically support reversible lithium-ion intercalation into graphite without solvent co-intercalation at conventional salt concentrations. In full cells using a graphite anode, they enable 10-fold higher energy densities compared to conventional ethers, and better thermal stability over carbonate electrolytes (operation up to 60 °C) by producing a robust solvent-derived solid electrolyte interphase (SEI). As single-solvent–single-salt electrolytes, they remarkably outperform carbonate electrolytes with fluoroethylene carbonate (FEC) and vinylene carbonate (VC) additives when cycled with graphite–silicon composite anodes. Our molecular design strategy opens a new class of electrolytes that can enable next generation Li-ion batteries with higher energy density and a wider working temperature window. 

Biology employs exquisite control over proton, electron, H-atom, or H 2 transfer. Similar control in synthetic systems has the potential to facilitate efficient and selective catalysis. Here we report a dihydrazonopyrrole Ni complex where an H 2 equivalent can be stored on the ligand periphery without metal-based redox changes and can be leveraged for catalytic hydrogenations. Kinetic and computational analysis suggests ligand hydrogenation proceeds by H 2 association followed by H–H scission. This complex is an unusual example where a synthetic system can mimic biology's ability to mediate H 2 transfer via secondary coordination sphere-based processes.