High-throughput Theoretical Studies On 2D Anchoring Materials For Li-S Batteries

Due to the great theoretical capacity,Li-S batteries are receiving widespread attention from academia and industry.However,the unrestricted migration(shuttle effect)and slow conversion kinetics of Li-S species severely degrade the actual performance,and anchoring materials have alleviated the two problems by adsorbing(anchoring)Li-S species.In recent years,researchers have greatly expanded the search space of anchoring materials through experimental and theoretical researches,and accelerating the searching of anchoring materials by combining density functional theory(DFT)with machine learning(ML)is becoming a new paradigm.This dissertation is aimed to further improve the efficiency of existing theoretical methods in revealing more general structure-property relationships for evaluating the anchoring effects,so as to better guide the design of new anchoring materials.This dissertation focuses on the 2-dimensional anchoring materials,and presents the following works and achievements.1.The anchoring of Li2S on 1255 kinds of binary two-dimensional materials have been calculated with DFT,which leads to the discovery of 44 kinds of promising anchoring materials.Besides,the overall anchoring strength is found to increase along with the "softness" of cation and the "hardness" of anion,which is consistent with the Hard-Soft-Acid-Base theory.2.Two ML models have been trained with the data from the previous work.One is the first tree-based model that captures the great impact of material geometry on anchoring strength.The other is the first graph neural network model that learns to predict crystal properties with Infomax mechanism.The latter model exhibits superior generalization ability,and assists the discovery of 372 kinds of potential anchoring materials from 1879 kinds of uncalculated materials.3.The anchoring of Li2S/Li2S2 on 1195 single-atom materials with 2D substrates have been calculated by DFT,and 6 kinds of them are considered promising in inhibiting shuttle effect and promoting Li-S conversion.The calculation results also show a possible scaling relationship between the anchoring strength and the catalytic activity for singleatom.In addition,the electronic structure analysis reflects the utility of d-band center of single-atom in regulating anchoring strength and catalytic activity.Based on the expansion of data for anchoring materials,the innovations of the above works mainly include the improved understandings of the structure-property relationships and the reasonable optimizations of ML models.This dissertation elucidates and demonstrates how the intrinsic material features(elemental composition and geometric structure)influence the anchoring effect,which provides directions for the regulation and design of anchoring materials in experiments.Moreover,the aforementioned achievements also reflect the necessity of the DFT+ML paradigm in future researches on anchoring materials.