Transference Number Reinforced-Based Gel Copolymer Electrolyte for Dendrite-Free Lithium Metal Batteries

Abstract

The progress of electric vehicles is highly inhibited by the limited energy density and growth of dendrite Li in current power batteries. Breakthroughs and improvements in electrolyte chemistry are highlighted to directly address the above issues, namely, the development of electrolytes with a high lithium-ion transference number (t Li + ), enabling one to effectively restrict the concentration polarization during repetitious cycling. Herein, we propose a novel ether-based copolymer-based gel polymer electrolyte (ECP-based GPE) by in situ copolymerization as an intriguing strategy to achieve a high t Li + of ∼0.64. Molecular dynamics simulations and finite element method analyses illustrate the enhanced Li + diffusion process (D Li + , ∼1.76 × 10 −10 m 2 s −1 ) in ECP-based GPE with a homogeneous electric potential accommodated around the lithium metal anode. Therefore, such a high-t Li + -based electrolyte renders a high reversibility of dendrite-free lithium plating/stripping at a high areal capacity (5 mA cm −2 /5 mA h cm −2 ) in an Li||Li symmetric cell and facilitates superior cycling performances (over 1000 cycles) at a high rate (5 C) with a capacity retention of ∼91.1% in Li||LiFePO 4 batteries, promoting the practical application of solid-state lithium metal batteries.

Gel Electrolyte for Li Metal Battery

“…Instead of the solvation of most of Li + by DOL/THF molecules in the liquid electrolyte (Figure 2a, b), the gel electrolyte significantly changes the solvation process of Li + according to the MD simulation, where most Li + ions directly contact with the FSI − anions which are immobilized by the fragment of gel electrolyte (Figure 2c). It will significantly enhance the Li + transport behavior [57] . To obtain a high t Li+ , the addition of high concentration of Li salts, small molecular solvents and fillers or functional modification of the polymer chains to fix the anions has been conducted, which will be elaborated hereinafter.…”

“…It will significantly enhance the Li + transport behavior. [57] To obtain a high t Li + , the addition of high concentration of Li salts, small molecular solvents and fillers or functional modification of the polymer chains to fix the anions has been conducted, which will be elaborated hereinafter.…”

Anin situformed copolymer electrolyte with high ionic conductivity and high lithium-ion transference number for dendrite-free solid-state lithium metal batteries

“…18 Up to now, PEs synthesized through an in situ polymerization method have been widely reported, including poly(vinylene carbonate) (PVC), 19 poly(methyl methacrylate) (PMMA), 20 poly-tetrahydrofuran (PTHF), 21 poly(triethylene glycol diacrylate) (PTEGDA), 22 poly(1,3-dioxolane) (PDOL) 23 and poly(trimethylpropane triacrylate) (ETPTA) 24 -based PEs. To further improve the interfacial compatibility, mechanical properties and the overall electrochemical performances of in situ polymerized PEs and SSBs, the strategies including integrations of inorganic llers, 24,25 making crosslinking polymers and copolymers, [26][27][28] and introducing functional groups into the polymer chains 19,29,30 have also been reported.…”

Designing strategies of advanced electrode materials for high-rate rechargeable batteries

“…[3][4][5][6] With the accelerating markets for EVs and desired transition towards clean energy, rechargeable batteries with fast charging capability are highly desired. [7][8][9] Compared with the rapid refuelling experience of the conventional internal-combustion engine vehicles (ICEs), battery electric vehicles (BEVs) take 2-6 h to be fully charged. This results in the poor motility of BEVs and consequently curtails the interest of customers to some degree.…”