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A*STAR researchers suggest monolayer phosphorene promising anode material for high-performance Li-ion batteries

Researchers at A*STAR in Singapore are proposing the use of monolayer phosphorene—a 2D material isolated from black phosphorus—as an anode material for high charging voltage, high rate capability Li-ion batteries. In a paper published in the ACS journal Nano Letters, they described their use of density functional theory calculations to investigate the binding and diffusion behavior of Lithium in phosphorene.

Phosphorus is a low-cost abundant material with a high theoretical specific capacity of 2596 mAh·g-1 upon lithiation with most of its capacity at the discharge potential range of 0.4–1.2 V, suitable as anodes. (Earlier post.) However, in a 2014 study led by Prof. Yi Cui, researchers at Stanford noted that successful applications of phosphorus anodes have been impeded by rapid capacity fading, mainly caused by large volume change (around 300%) upon lithiation and thus loss of electrical contact. In that 2014 study, the Stanford researchers fabricated composites of black phosphorus nanoparticle-graphite; the resulting material exhibited high initial discharge capacity of 2786 mAh·g-1 at 0.2 C and cycle life of 100 cycles with 80% capacity retention.

High specific discharge capacities were maintained at fast C rates (2270, 1750, 1500, and 1240 mAh·g−1 at C/5, 1, 2, and 4.5 C, respectively.

Further, in the ongoing quest to develop rechargeable batteries with high capacity and high rate capability, many researchers are investigating novel electrode architectures using 2D nanomaterials such as graphene.

Very recently, a new 2D material, phosphorene, has been successfully isolated from black phosphorus. The phosphorene monolayer consists of P atoms stacked in puckered subplanes. Each P atom is bonded with two adjacent atoms lying in the same plane and with one P atom from a different plane. Black phosphorus, the bulk form, can be formed by stacking phosphorene monolayer through weak interlayer van der Waals (vdW) interaction with an interlayer distance of 3.09 Å. Then, an interesting question arises naturally and promptly: Is monolayer phosphorene a promising anode material for Li-Battery? To answer this question, a detailed study on the Li adsorption and diffusion process in monolayer phosphorene is indispensable.

—Li et al.

Among the findings of the A*STAR researchers were:

  1. Li atom forms strong binding with phosphorus atoms and exists in the cationic state.

  2. Modulated by its puckered structure, the diffusion of Li on phosphorene is highly anisotropic with diffusion along the zigzag direction being highly energetically favorable, while diffusion along the armchair direction is almost prohibited. Specifically, the energy barrier along the zigzag direction is only 0.08 eV for Li in monolayer phosphorene, much lower than that in two other Li-Battery anode candidates, graphene and MoS2. The shallow energy barrier leads to an ultrahigh diffusivity, which is estimated to be 102 (104) times faster than that on MoS2 (graphene) at room temperature;

  3. The large energy barrier (0.68 eV) along armchair direction results in a nearly forbidden diffusion; such strong diffusion anisotropy is absent in graphene and MoS2.

  4. The average voltage of the Li intercalation is estimated to be 2.9 V, suitable for high charging voltage applications.

  5. A semiconducting to metallic transition induced by Li intercalation of phosphorene gives rise to a good electrical conductivity, ideal for use as an electrode.

On the basis of our present findings, monolayer phosphorene is expected to be used in novel electronic device and Li-Battery with a high charging voltage and high rate capability.

—Li et al.


  • Weifeng Li, Yanmei Yang, Gang Zhang, and Yong-Wei Zhang (2015) “Ultrafast and Directional Diffusion of Lithium in Phosphorene for High-Performance Lithium-Ion Battery” Nano Letters doi: 10.1021/nl504336h

  • Jie Sun, Guangyuan Zheng, Hyun-Wook Lee, Nian Liu, Haotian Wang, Hongbin Yao, Wensheng Yang, and Yi Cui (2014) “Formation of Stable Phosphorus–Carbon Bond for Enhanced Performance in Black Phosphorus Nanoparticle–Graphite Composite Battery Anodes” Nano Letters 14 (8), 4573-4580 doi: 10.1021/nl501617j



The volume change issues with black phosphorous and silicon can be addressed by use of binders with a more elastic nature. It is a topic of research pursued by a number of researchers, and I think some progress is being made. So while, yes, the loss of contact that happens because of volume change in Si and Phosphorous anodes when implemented with the standard anode binder materials is an immediate issue, there should not necessarily be the expectations that a more suitable elastic binder system cannot be developed.

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