Preparation Of Monoatomic/Quantum Dots Hybrid Carbon Foams And Stablization Of Sodium Metal Anodes

Developing low cost,high capacity and long life chemical power supply is the key to promote the sustainable development of electric vehicles and electronic products.Due to the high theoretical capacity,low potential and abundant reserves of sodium metal,the development of sodium metal batteries has become a hot research topic.However,the unstable solid electrolyte interface（SEI）,dendrites,and large volume changes at the anode of sodium metals pose great challenges such as low coulomb efficiency（CE）,short cycle life,and serious safety hazards.Constructing three-dimension（3D）porous carbon hosts is one of the most effective ways to regulate the nucleation and growth of Na by reducing local current density and providing Na accommodation space.However,how to design multifunctional 3D carbon hosts is still a great challenge.Here,a metal-organic-frameworks（MOFs）derived strategy is proposed to design Ni monoatom/quantum dots hybrid carbon foams（Ni SA/QD@CFs）.The Ni SA/QD@CFs owns ultrahigh porosity of90.16%,large pore volume of 4.71 cm³/g,and low density of 0.19 g/cm³.The uniformly distributed Ni atoms and QDs serve as nucleating sites to effectively regulate the initial nucleation and smooth growth of Na.Moreover,the interconnected macropores provide abundant three-dimensional Na-containing space,and effectively inhibits dendritic growth.Therefore,under the condition of 1 m A cm^-2,1 m Ah cm^-2,the SMAs half-cell based on Ni SA/QD@CFs can be cycled stably for 2000cycles with a coulombic efficiency as high as 99.8%.Symmetrical cell exhibits low polarization voltage of 8 m V and stable cycling for 2700 h.Moreover,after 400 cycles at 1 A g^-1（>8 C）,the capacity of the full cell with Na₃V₂（PO₄）₃cathode can still reach 88.8 m Ah g^-1,and the retention rate is as high as 95.69%,showing a good stability.This strategy opens up a new and facile designing platform from MOFs to hybrid carbon foams for new energy application.