Defective BC₂N as an Anode Material with Improved Performance for Lithium-Ion Batteries

Abstract

Defect engineering can modify the physical and chemical properties of two-dimensional (2D) materials to advance their effectiveness for applications. Here, we have designed three kinds of single carbon vacancies (VC‑I of BC2N-II as well as VC‑III and VC‑IV of BC2N-III) to systematically investigate their Li adsorption and diffusion performance based on DFT calculations. The electronic structure analysis shows that the existence of the defects plays a crucial role to tune the electronic properties and the performance of BC2N-II and BC2N-III monolayers toward the potential application as anodes of lithium-ion batteries (LIBs). Significantly, compared to the pristine BC2N-II and BC2N-III monolayers that can hardly adsorb Li atoms, defective BC2N monolayers greatly enhance the Li adsorption energy. In addition, the theoretical capacities of defective BC2N monolayers, especially for VC‑I of BC2N-II (2256 mAh/g), are extremely high, but the energy barriers of Li transfer in the vicinity of the defective BC2N are relatively large, whereas for escaping defective sites, these levels are comparatively small. Considering the diffusion behavior of Li in the actual process of Li insertion in the anode of the LIBs, we further explored the adsorption and diffusion performance of Li on the modified VC‑I monolayer with one Li atom occupying the most stable position (site H) of the defect. Remarkably, the Li can shuttle between the stable sites around the defects with energy barriers as low as 0.45 eV. The calculated voltages for all systems are all within the desired ranges of reported anode materials for LIBs. Our findings provide a theoretical guideline to design reasonable anode materials with defect for LIBs.

Nanohybrids of BCN‐Fe1−xS for Sodium and Lithium Hybrid Ion Capacitors

“…[16,17] On the other hand, the hexagonal BCN crafted with suitable defects were predicted, with DFT simulations, as high-performance anode materials for Li-ion batteries. [18] DFT calculations by Jiang et al provided insight into the mechanism underlying the wide operating voltage range of cationic and anionic BCN sheets for lithium-ion capacitor (LIC) applications. [19] On the other hand, iron sulfide is a promising candidate for the anodes in LIBs, however, it suffers from volume change during cycling and weak conductivity.…”

First-Principles Study of 2D Haeckelite C7N as a High-Capacity Anode for Post-Lithium-Ion Batteries

“…11 Given these restrictions, hope lies in using two-dimensional (2D) materials with their promising structural features, such as expanded interlayer spacing and a high aspect ratio, which can alleviate structural instability caused by those bulky post-Li atoms. 12 In pursuit of high-performing anodes for post-Li batteries, numerous 2D materials have been proposed, including MoS 2 , 13 MXenes, 1 and graphite analogues such as C 2 N, 14 Si 2 BN, 15 B x N, 16 and BC 2 N. 17 However, many of them do not have intrinsic metallic properties, resulting in poor rate performance and cycling, 18 in an operating anode. 16,19 In contrast to graphite/graphene anodes for Li batteries, these materials fall short of meeting the minimum requirements of a practical anode, such as being lightweight, conductive, cost-effective, and widely available on the earth's crust.…”

“…In pursuit of high-performing anodes for post-Li batteries, numerous 2D materials have been proposed, including MoS 2 , MXenes, and graphite analogues such as C 2 N, Si 2 BN, B x N, and BC 2 N . However, many of them do not have intrinsic metallic properties, resulting in poor rate performance and cycling, or are not flat, creating tortuous diffusion paths in an operating anode. , In contrast to graphite/graphene anodes for Li batteries, these materials fall short of meeting the minimum requirements of a practical anode, such as being lightweight, conductive, cost-effective, and widely available on the earth’s crust.…”

First-principles study of two-dimensional C-silicyne nanosheet as a promising anode material for rechargeable Li-ion batteries

“…2 Over the past few decades, Li-ion batteries (LIBs) have dominated the sector of energy storage owing to their high energy/power density, reversible capacity, no memory effect, and long cycle stability. 3,4 From transportation to consumer electronics, LIBs play a significant role in electric vehicles, portable devices, power tools, etc. [5][6][7] However, to use LIBs in electrical vehicles and for other high-end applications, there is a need to increase their energy density.…”