An electron-deficient carbon current collector for anode-free Li-metal batteries

Abstract

The long-term cycling of anode-free Li-metal cells (i.e., cells where the negative electrode is in situ formed by electrodeposition on an electronically conductive matrix of lithium sourced from the positive electrode) using a liquid electrolyte is affected by the formation of an inhomogeneous solid electrolyte interphase (SEI) on the current collector and irregular Li deposition. To circumvent these issues, we report an atomically defective carbon current collector where multivacancy defects induce homogeneous SEI formation on the current collector and uniform Li nucleation and growth to obtain a dense Li morphology. Via simulations and experimental measurements and analyses, we demonstrate the beneficial effect of electron deficiency on the Li hosting behavior of the carbon current collector. Furthermore, we report the results of testing anode-free coin cells comprising a multivacancy defective carbon current collector, a LixNi0.8Co0.1Mn0.1-based cathode and a nonaqueous Li-containing electrolyte solution. These cells retain 90% of their initial capacity for over 50 cycles under lean electrolyte conditions.

Rationalized design of hyperbranched trans-scale graphene arrays for enduring high-energy lithium metal batteries

“…The intensity ratio of these defects to sp 2 -hybridized carbon is 0.35 (calculated on the basis of the integral areas of the peaks), indicative of a high defect population. The peak centred at 284.1 eV represents the carbon vacancies at the lattice sites, and the peak at 285.2 eV can be assigned to nonconjugated carbon that mostly include hydrogenated carbon ( 30 , 31 ). Vacancies in graphene have been proved able to induce the formation of Li-intercalated states with a high lithium-to-carbon ratio such as Li 3 C 8 ( 32 ), compared to the common LiC 6 .…”

Rational Engineering of Anode Current Collector for Dendrite-Free Lithium Deposition: Strategy, Application, and Perspective

“…The produced multi-channels provided sufficient space for volume changes of lithium, while Ag nanoparticles ensured homogeneous nucleation and deposition. Kwon et al (2021 ) synthesized an atomically defective carbon current collector with multivacancy defects using the surface-oxidized carbon fiber paper to induce homogeneous SEI formation and uniform lithium growth. Polymers usually contain a number of polar groups, such as hydroxyl, nitro, and carboxyl, which possess excellent lithiophilicity.…”

“…The capacity retention of the anode-free cell was improved from 13.3% to ∼73.3% after 50 cycles. The atomically defective carbon current collector invented by Kwon et al (2021 ) successfully elevated the capacity retention of AFLMB to 90% over 50 cycles under lean electrolyte conditions. Lin et al (2021 ) applied an epitaxial induced plating current collector (E-Cu) with a GaInSn liquid metal (LM) layer to facilitate Li + diffusion and initiate epitaxial growth of lithium, resulting in increased capacity retention from 66% to 84% in 50 cycles of an anode-free NCM811||E-Cu pouch cell with a remarkable energy density of 420 Wh/kg.…”

Controlled Lithium Deposition

“…This pre-lithiation behavior enhances their affinity with the deposited lithium. Various carbon materials (few-layer graphite or multilayer graphene Deng et al, 2018;Liu W. et al, 2019;Ren et al, 2019), carbon nanotubes (Wang Y. et al, 2017;Guo et al, 2018;Guo et al, 2019), carbon fiber (Lin et al, 2019;Liao et al, 2020;Kwon et al, 2021), etc.) have been proved effective for mitigating the Li dendrite growth due to their porous structure and/or affinity with lithium.…”

“…have been proved effective for mitigating the Li dendrite growth due to their porous structure and/or affinity with lithium. Kwon et al (Kwon et al, 2021) reported an atomically defective carbon current collector where multi-vacancy defects induce homogeneous SEI formation, uniform lithium nucleation and growth to obtain a dense lithium morphology. Zuo et al (Zuo et al, 2017) developed graphitized carbon fiber electrode to enhance the Li storage capacity (Figure 1A).…”