Natural “relief” for lithium dendrites: Tailoring protein configurations for long-life lithium metal anodes
- Award ID(s):
- 1929236
- PAR ID:
- 10283112
- Date Published:
- Journal Name:
- Energy Storage Materials
- Volume:
- 42
- Issue:
- C
- ISSN:
- 2405-8297
- Page Range / eLocation ID:
- 22 to 33
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
Abstract All‐solid‐state batteries with metallic lithium (LiBCC) anode and solid electrolyte (SE) are under active development. However, an unstable SE/LiBCCinterface due to electrochemical and mechanical instabilities hinders their operation. Herein, an ultra‐thin nanoporous mixed ionic and electronic conductor (MIEC) interlayer (≈3.25 µm), which regulates LiBCCdeposition and stripping, serving as a 3D scaffold for Li0ad‐atom formation, LiBCCnucleation, and long‐range transport of ions and electrons at SE/LiBCCinterface is demonstrated. Consisting of lithium silicide and carbon nanotubes, the MIEC interlayer is thermodynamically stable against LiBCCand highly lithiophilic. Moreover, its nanopores (<100 nm) confine the deposited LiBCCto the size regime where LiBCCexhibits “smaller is much softer” size‐dependent plasticity governed by diffusive deformation mechanisms. The LiBCCthus remains soft enough not to mechanically penetrate SE in contact. Upon further plating, LiBCCgrows in between the current collector and the MIEC interlayer, not directly contacting the SE. As a result, a full‐cell having Li3.75Si‐CNT/LiBCCfoil as an anode and LiNi0.8Co0.1Mn0.1O2as a cathode displays a high specific capacity of 207.8 mAh g−1, 92.0% initial Coulombic efficiency, 88.9% capacity retention after 200 cycles (Coulombic efficiency reaches 99.9% after tens of cycles), and excellent rate capability (76% at 5 C).more » « less
-
Lithium metal batteries promise higher energy densities than current lithium-ion batteries but require novel electrolytes to extend their cycle life. Fluorinated solvents help stabilize the solid electrolyte interphase (SEI) with lithium metal, but are believed to have weaker solvation ability compared to their nonfluorinated counterparts and are deemed ‘poorer electrolytes’. In this work, we synthesize tris(2-fluoroethyl) borate (TFEB) as a new fluorinated borate ester solvent and show that TFEB unexpectedly has higher lithium salt solubility than its nonfluorinated counterpart (triethyl borate). Through experiments and simulations, we show that the partially fluorinated –CH2F group acts as the primary coordination site that promotes lithium salt dissolution. TFEB electrolyte has a higher lithium transference number and better rate capability compared to methoxy polyethyleneglycol borate esters reported in the literature. In addition, TFEB supports compact lithium deposition morphology, high lithium metal Coulombic efficiency, and stable cycling of lithium metal/LiFePO4 cells. This work ushers in a new electrolyte design paradigm where partially fluorinated moieties enable salt dissolution and can serve as primary ion coordination sites for next-generation electrolytes.more » « less
An official website of the United States government

