Combining Neural Network with First-Principles Calculations for Computational Screening of Electrolyte Additives in Lithium-Ion Batteries

Lithium-ion batteries (LIBs) are widely used in portable devices, such as mobile phones and laptops. To extend the application to large power equipment, some of which are electric vehicles and residence energy storage, the energy density and capacity of the batteries should be improved [1, 2]. A typical LIB is composed of one graphitic anode, one transition-metal oxide as a cathode, and electrolyte. LiCoO₂, LiMn₂O₄, and LiFePO₄ are the conventional materials for cathode; graphite, silicon 126nanoparticles, and carbon composites are for an anode. There are several different formulas for electrolytes [3], usually consisting of organic compounds, including ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), lithium salt, and functional additives [4, 5]. The environment components in a battery with which additive would have interactions are the electrolyte, lithium ions, and hydrogen fluoride (HF). In this work, 185 electrolyte additives molecules reported in past articles have been collected and classified into six different categories [6, 7] as follows:

Solid electrolyte interphase (SEI)-forming improver and SEI morphology modifier:

Vinylene carbonate (VC) [8–10], vinyl ethylene carbonate (VEC) [11], ally ethyl carbonate (AEC) [12], vinyl acetate (VA), SO₂, polysulfide (S_x ^2-), ethylene sulfite (ES) [5, 13], fluoroethylene carbonate (FEC) [14, 15], propylene sulfite (PS) [16], and so on

Electrode protection agent:

N,N’-dicyclohexylcarbodiimide, N,N-diethylamino trimethylsilane (DEATMS) [17], and so on

LiPF₆ salt stabilizer:

Tris(2,2,2-trifluoroethyl) phosphite (TTFP), 1-methyl-2-pyrrolidinone (NMP), hexamethyl phosphoramide (HMPA), and so on

Safety protection agent:

Metallocenes, tetracyanoethylene, tetramethyl phenylenediamine, and so on

Li deposition improver:

2-Methyltetrahydrofuran, 2-methyl thiophene [17], nitromethan, and so on

Electrolytes’ physical properties modifier:

Tris(pentafluorophenyl) borane (TPFPB) [18], trialkyl phosphate, methyl decanoate, dodecyl acetate, and so on