F-Doped carbon nano-onion films as scaffold for highly efficient and stable Li metal anodes: a novel laser direct-write process

Abstract

Li metal is the most promising choice for anode in high-energy rechargeable batteries, but the dendrite growth upon cycling leads to safety concerns and poor cycle life. Herein, we demonstrate a novel and scalable approach for direct writing of a thin layer of carbon nano-onions on copper substrate to stabilize the Li metal anode and prevent the dendrite growth. The F-doped carbon nano-onion film (F-CNOF) scaffold enables reversible electroplating for over 1500 hours (300 cycles) with a coulombic efficiency of ∼100%. The F-CNOF is capable of depositing Li equivalent to a capacity of 10 mA h cm-2 (gravimetric capacity 3218 mA h g-1) at 1 mA cm-2, operating at a high current density of 6 mA cm-2. More importantly, these features of long-term cyclic stability and excellent rate capability are attributed to the very high curvature due to nano dimension (∼108 m-1) of the nano-onions that develop a very uniform Li flux due to the negative surface charge, thus preventing the dendrite formation. We have also shown via first-principles DFT calculations that the high curvature achieved herein can significantly enhance the binding energy of Li to the carbon surface, which helps to improve lithiophilicity. A full cell fabricated using Li4Ti5O12 as the positive electrode showed cyclic stability of 450 cycles.

Carbon Nano‐Onions: A Review of Recent Progress in Synthesis and Applications

“…The first strategy is based on doping by heteroatoms during the formation of CNs, and the second strategy is connected to the post‐synthesis treatment of already‐formed CNs using different oxidizing or reducing agents. For this purpose, doping CNOs with N, B, F, O and S was performed …”

“…Next, very interesting direct modification of the CNO nanostructures was performed by Puthusseri and coworkers . A scalable approach for direct laser writing of a thin layer of CNOs on copper substrate was reported.…”

“…For this purpose, doping CNOs with N, B, F, O and S was performed. [138][139][140][141][142][143][144] Boron-doped CNOs (B-CNOs) were obtained using an in situ method during electron irradiation of a graphitic material in a TEM and via chemical vapour deposition of BCl 3 and C 6 H 6 . [145,146] The direct preparation of CNOs via thermal annealing of NDs using a boron source (H 3 BO 3 or amorphous powder of boron) or nitrogen was recently reported.…”

“…Next, very interesting direct modification of the CNO nanostructures was performed by Puthusseri and coworkers. [142] A scalable approach for direct laser writing of a thin layer of CNOs on copper substrate was reported. This method was based on scanned pulsed CO 2 laser irradiation of a polyvinylidene fluoride film coated on the copper foil, which led to direct formation of fluoro-doped CNOs (F-CNOs).…”

Suppressing Lithium Dendrite Growth via Sinusoidal Ripple Current Produced by Triboelectric Nanogenerators

“…[4][5][6][7] To realize viable application of Li metal anodes, continuous effort has been made for years to understand the mechanism of Li deposition and tackle the formation of dendrites. [24][25][26][27][28][29] For examples, Guo et al reported that 3D Cu with a large number of charge centers and nucleation sites facilitate the formation of relatively even Li surface. [24][25][26][27][28][29] For examples, Guo et al reported that 3D Cu with a large number of charge centers and nucleation sites facilitate the formation of relatively even Li surface.…”