Free-Standing N, P Codoped Hollow Carbon Fibers as Efficient Hosts for Stable Lithium Metal Anodes

Abstract

Constructing 3D hosts has been verified to be an effective strategy to control Li plating/stripping behaviors. Herein, free-standing N, P codoped hollow carbon fibers (NPHCFs) are prepared and regarded as efficient host materials, which can provide more lithiophilic nucleation sites and more volume to accommodate the Li metal. scanning electron microscopy (SEM) images suggest that the Li metal is confined to both the interspace and the inside of hollow carbon fibers without uncontrollable Li dendrites. An initial Coulombic efficiency (>94.6%) is obtained for over 500 h for the NPHCF host at 0.5 mA cm −2 and 0.5 mAh cm −2 . The NPHCF@Li symmetric cell successfully runs over 250 cycles at 0.5 mA cm −2 and 0.5 mAh cm −2 without obvious voltage fluctuations. More impressively, the NPHCF@Li||LiFePO 4 full cell delivers a first specific discharge capacity of 164 mAh g −1 and an enhanced capacity retention ratio of ∼72.13% after 100 cycles at 0.2 C. These better results indicate that N and P cointroduced into hollow carbon fibers may be a feasible strategy to develop high-energy lithium metal anodes. This work further indicates the feasibility to develop Li metal anodes by designing lithiophilic host materials.

Carbon/Lithium Composite Anode for Advanced Lithium Metal Batteries: Design, Progress, In Situ Characterization, and Perspectives

“…At the same time, high specific surface area can effectively decrease the regional electric field and promote stable and uniform Li plating. Yang's group [ 73 ] reported the fabrication of free‐standing N/P co‐doped hollow carbon fiber (NPHCFs) as an effective carrier for stabilizing LMA using hollow polypyrrole (PPy) fiber as a template. Benefiting from N/P co‐doped, NPHCFs hosts show improving lithiophilic ability with low Li nucleation overpotential.…”

Advances in Nanofibrous Materials for Stable Lithium-Metal Anodes

“…For instance, N and P codoped hollow carbon fibers not only provided more lithiophilic sites, but also provided a larger accommodation space for lithium metal volume variations. 98 Niu et al designed the amine-functionalized mesoporous CNFs, as shown in Figure 7a, the amine functional group improved the lithiophilicity of the CNFs, and the mesopores on the CNFs surface are always the preferred nucleation sites for Li + , thus achieving a self-smoothing LMA. 99 LMBs assembled using this composite LMA paired with commercial NMC622 and MNC811 (LiNi 0.8 Mn 0.1 Co 0.1 O 2 ) cathodes delivered large energy densities of 350−380 Wh kg −1 and long cycle lives up to 200 cycles.…”

“…Furthermore, the combination of heteroatom doping and pore structure in CNFs can provide better performance. For instance, N and P codoped hollow carbon fibers not only provided more lithiophilic sites, but also provided a larger accommodation space for lithium metal volume variations . Niu et al designed the amine-functionalized mesoporous CNFs, as shown in Figure a, the amine functional group improved the lithiophilicity of the CNFs, and the mesopores on the CNFs surface are always the preferred nucleation sites for Li + , thus achieving a self-smoothing LMA .…”

Columnar Lithium Deposition Guided by Graphdiyne Nanowalls toward a Stable Lithium Metal Anode

“…For example, a two-dimensional (2D) Cu substrate modified with a hollow carbon nanosphere layer, a hollow semigraphitic carbon-coated SiO x /C microsphere layer, and a three-dimensional (3D) Ni skeleton coated with onion-like carbon granules allowed for stable Li metal anodes. Furthermore, 3D porous carbon-based materials , and 3D frameworks formed by carbon fibers − were prepared as 3D current collectors to stabilize Li metal anodes. Interestingly, a variety of carbon nanomaterials including carbon nanotubes − and graphene − were successfully used for fabricating stable Li metal anodes.…”