Search

Alloy Sb as an anode material for Li ion batteries (LIBs) suffers from severe volume expansion and structural breakdown during lithiation process, leading to a abrupt drop of battery cycle performance. The density functional theory is used to explore the adsorption and diffusion of Li atom in the two dimensional graphene/β-antimonene (G/Sb) heterostructure. Our calculation results reveal that the G/Sb heterostructure possesses excellent thermodynamic and dynamic stability with the 0.06 eV band gap, which is much smaller than that of monolayer Sb (1.24 eV) and can insure fast electron transport in the electrode during lithiation/delithiation process. The calculated smaller Li diffusion energy barrier and volume expansion, together with the larger Li diffusion coefficient at 300 K explore greater charge/discharge performance for the G/Sb heterostructure than the corresponding parent bulk, monolayer, and bilayer materials. This is mainly because the monolayer β-Sb within the G/Sb heterostructure can render larger strain compared with that of the pristine β-Sb. We also evaluate the performance of the G/Sb heterostructure as the anode of LIBs by charge analysis and density of states. These results provide conclusive evidence to explore that the G/Sb heterostructure should be a promising candidate anode for flexible and wearable LIBs. Unlabelled Image • The diffusion coefficient of the G/Sb heterostructure is 112 times of that of bilayer β-Sb. • The G/Sb heterostructure can give rise to greater charge/discharge performance than the bulk, monolayer, and bilayer materials. • The volume expansion of G/Sb heterostructure is 1% which is far small than 200% of Sb metal(200%), monolayer Sb(15%) and bilayer Sb(-6%). • The lithiated G/Sb heterostructure show excellent dynamical stability, indicating it is promising candidate for the Li-ion battery anode. • The average open circuit voltage of 0.42 V for the bilayer β-Sb is ideal for Li ion battery. [ABSTRACT FROM AUTHOR]

[Display omitted] • Amorphous Al 2 O 3 in porous carbon anchored on carbon cloth was first fabricated. • The composite was investigated as a multifunctional interlayer for Li-S batteries. • The Li-S cells with high sulfur-loading exhibited superior cycling stability. • The Li-S cells exhibited excellent rate capability. • The amorphous Al 2 O 3 in porous carbon can effectively suppress the LPS shuttle effect. To realize practical applications of lithium-sulfur batteries, rational strategies have to be applied to overcome obstacles such as the shuttle effect and sluggish reaction kinetics of soluble long-chain lithium polysulfides (LPS). In this work, highly electrocatalytic active amorphous Al 2 O 3 uniformly dispersed in porous carbon (Al 2 O 3 /C) anchored on carbon cloth (CC) was successfully fabricated. The resultant flexible Al 2 O 3 /C@CC was used as an independent interlayer for Li-S batteries, demonstrating strong physical confinement and chemical binding ability for LPS, as well as high catalytic activity for LPS conversion kinetics due to a synergistic effect of 3D conductive network, amorphous nature of Al 2 O 3 /C, porous structure and abundant active sites. The cells with such interlayer exhibit high specific capacity, superior cycling stability and rate capability, 903 mAh/g at 0.2C after 100 cycles and 810 mAh/g at 1.0C after 300 cycles can be achieved, moreover, 741 mAh/g can still be retained at a high rate of up to 5.0C. By contrast, Al-MOF grown on carbon cloth (Al-MOF@CC) exhibits limited performance improvement due to poor electrical conductivity, low structure stability, as well as limited ion diffusion rate and weak Lewis acid-base interactions due to lack of open channels. [ABSTRACT FROM AUTHOR]

An effective avenue to develop nonmetal atoms doped 2D Ti 2 CO 2 catalysts with integrating DFT calculations, nonmetal single atom valence electron number and bader electron transfer coupled electron descriptor and electronic structure validations. [Display omitted] • We implanted 14 kinds of nonmetal atoms into Ti 2 CO 2 to improve the HER activity. • Good HER catalytic activity and conductivity could be simultaneously achieved. • Coupling descriptor could accurately predict HER catalytic activity trends. • High-throughput computing combination descriptor is an effective avenue to develop HER catalysts. 2D MXenes, with large surface area, good conductivity, adjustable hydrophilic and varies surface functional groups, are potential catalyst for hydrogen evolution reaction (HER). In this work, 14 kinds of nonmetal (NM) single atom doped 2D Ti 2 CO 2 catalysts were screened by DFT method. It was found that the surface doping of nonmetal single atom can effectively promote the HER activity of Ti 2 CO 2. Among them, Ti 2 CO 2 with rich fluorine termination groups realizing efficient electrocatalytic HER has been successfully verified by recent experiments. Through the analysis of electronic structure, it is found that nonmetal single atom valence electron number and bader electron transfer coupled electron descriptor is suitable to accurately predict the trend of 2D NM-Ti 2 CO 2 catalytic activity for HER. The large-scale screening of this work and the mechanism analysis of nonmetal single atom surface doping enhanced of 2D Ti 2 CO 2 HER activity not only provide a database reference for the experimental synthesis of NM-MXenes HER catalyst, but also provide a electronical mechanism guidance for the extensive design of new NM- MXenes materials. [ABSTRACT FROM AUTHOR]

The safety and poor reversibility of the lithium-ion batteries (LIBs) are usually induced by the large volume expansion existing during the lithiation process. Thus, the good reversibility and high Li capacity is necessary to be balanced in the electrode materials. The density functional theory is used to explore the adsorption and diffusion of Li ions on bilayer two-dimensional (2D) β-antimonene (β-Sb) as the anode material. The metallic property of Li adsorbed bilayer β-Sb can insure fast electron transport in the electrode during lithiation/delithiation process, which is important for the electrode materials of LIBs. The moderate adsorption energy and diffusion mobility of Li atoms on the bilayer β-Sb explores its good Li storage capacity. Importantly, the AA-stacking bilayer β-Sb has only 4% volume expansion in the Li adsorption process, which is much smaller than the 200% of Sb metal and indicates it is well-kept upon adsorption of Li even at the maximum concentration, suggesting it can avoid the rapid attenuation of electrode capacity in the charge-discharge cycle. Excellent performances of Li capacity and diffusion ability make AA-stacking bilayer β-Sb as the promising candidates for the anode material of LIBs. Unlabelled Image • The metallic property of Li adsorbed bilayer β-Sb can insure fast electron transport during lithiation process. • The electrical conductivity of bilayer β-Sb is higher than that of monolayer β-Sb. • The 4% volume expansion of AA-stacking bilayer β-Sb can avoid the rapid attenuation of electrode capacity. • The Li diffusibility of bilayer β-Sb is 104(105, 108)times is faster than that on 2D SnS 2 (InP 3 , Sb metal). • Excellent Li capacity and diffusion ability make AA-stacking bilayer β-Sb promising LIB anodes. [ABSTRACT FROM AUTHOR]