Morphologically and chemically regulated 3D carbon for Dendrite-free lithium metal anodes by a plasma processing

For the high theoretical specific capacity and low redox potential, lithium (Li) metal is considered as one of the most promising anode materials for the next generation of rechargeable batteries. In this work, we have developed an effective and accurate plasma strategy to regulate the surface morphology and functional groups of three-dimensional nitrogen-containing carbon foam (CF) to control the Li nucleation and growth. Besides the rougher surface induced by oxygen (O₂) plasma, the conversion of carbon-nitrogen chemical bond (CN), namely, change from the quaternary N to pyrrolic/pyridinic N was realized by the nitrogen (N₂) plasma. This chemical regulation of nitrogen boosts the lithiophilicity of carbon foam, which is evidenced by lower overpotential obtained from the experiment and higher binding energy for Li ions (Li⁺) calculated by density functional theory (-1.43, -1.85, -2.41 and -2.45 eV for the amorphous C-, C-quaternary N-, C-pyrrolic N- and C-pyridinic N-, respectively). The electrochemical performance of the half cells and full cells based on this plasma regulated carbon foam collectors also proved the prominent effectiveness of this plasma strategy on guiding the uniform dispersion of Li⁺ and thus inducing the homogeneous Li nucleation, as well as suppressing the growth of Li dendrites.