Abstract
As the search for new battery chemistries with higher capacities and more stable supply chains expands, requiring increasingly complex electrolytes with multiple solvents and anions, it is becoming clear that understanding and controlling the working cation solvation structure is key to enabling improved stability and reversibility. In this work, we discover an emergent solvation behavior in multivalent electrolytes containing multiple anions, where bis(trifluoromethane sulfonyl) imide (TFSI−) anions that are fully dissociated in isolation form contact ion pairs with Zn2+ when combined with more strongly coordinating halides. This coordination modifies the electrochemical response, activating additional redox species as the halide association strength weakens (i.e., Cl− > Br− > I−) and systematically lowering overpotentials for metal deposition. This work suggests a completely new framework for electrolyte design in which anion chemistry can be used to tune both the bulk speciation and the interfacial solvation structure, enabling profound changes to the electrochemical behavior of the system.
| Original language | English |
|---|---|
| Pages (from-to) | 1955-1971 |
| Number of pages | 17 |
| Journal | Chem |
| Volume | 9 |
| Issue number | 7 |
| DOIs | |
| State | Published - Jul 13 2023 |
| Externally published | Yes |
Funding
This work was supported as part of the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the U.S. Department of Energy , Office of Science , Basic Energy Sciences . This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science user facility at Argonne National Laboratory. Electrochemical measurements and Raman spectroscopy were performed at the Electrochemical Discovery Laboratory, a JCESR facility at Argonne National Laboratory. We acknowledge a generous grant of computer time from the Argonne National Laboratory Computing Resource Center (Bebop). We also acknowledge the computational resources from Center for Nanoscale Materials, an Office of Science user facility, which was supported by the U.S. Department of Energy , Office of Science , Office of Basic Energy Sciences under contract no. DE-AC02-06CH11357 . This work was supported as part of the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science user facility at Argonne National Laboratory. Electrochemical measurements and Raman spectroscopy were performed at the Electrochemical Discovery Laboratory, a JCESR facility at Argonne National Laboratory. We acknowledge a generous grant of computer time from the Argonne National Laboratory Computing Resource Center (Bebop). We also acknowledge the computational resources from Center for Nanoscale Materials, an Office of Science user facility, which was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract no. DE-AC02-06CH11357. D.M.D. S.N.L. M.B. and J.G.C. conceived the idea and designed the experiments. D.M.D. performed XAS measurements, data analysis, and related modeling under the supervision of M.B. T.T.F. performed additional XAS measurements. S.N.L. performed Raman spectroscopy, SEM imaging, and DFT calculations of Raman vibrational modes under the supervision of J.G.C. M.Z. and S.I. performed electrochemical measurements and analysis under the supervision of D.S. and J.G.C. P.C.R. and G.A. performed DFT calculations of complex free energies of formation and redox potential under the supervision of L.C. and R.S.A. D.M.D. and J.G.C. drafted the manuscript, and all authors discussed the results and contributed to revisions. The authors declare no competing interests.
Keywords
- SDG7: Affordable and clean energy
- anion association
- electrodeposition
- electrolyte design
- multivalent battery
- solvation structure