Dendrite–Free Potassium Metal Anodes in a Carbonate Electrolyte

Journal Article · 20 December 2019 · Advanced Materials

DOI: https://doi.org/10.1002/adma.201906735 · OSTI ID:1606027

Liu, Pengcheng  ^[1]; Wang, Yixian ^[1]; Gu, Qilin ^[2]; Nanda, Jagjit  ^[3]; Watt, John Daniel  ^[4]; Mitlin, David  ^[1]

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1. Univ. of Texas, Austin, TX (United States)
2. National Univ. of Singapore (Singapore)
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Potassium (K) metal anodes suffer from a challenging problem of dendrite growth. In this study, it is demonstrated that a tailored current collector will stabilize the metal plating–stripping behavior even with a conventional KPF₆–carbonate electrolyte. A 3D copper current collector is functionalized with partially reduced graphene oxide to create a potassiophilic surface, the electrode being denoted as rGO@3D–Cu. Potassiophilic versus potassiophobic experiments demonstrate that molten K fully wets rGO@3D–Cu after 6 s, but does not wet unfunctionalized 3D–Cu. Electrochemically, a unique synergy is achieved that is driven by interfacial tension and geometry: the adherent rGO underlayer promotes 2D layer–by–layer (Frank–van der Merwe) metal film growth at early stages of plating, while the tortuous 3D–Cu electrode reduces the current density and geometrically frustrates dendrites. The rGO@3D–Cu symmetric cells and half–cells achieve state–of–the–art plating and stripping performance. Here, the symmetric rGO@3D–Cu cells exhibit stable cycling at 0.1–2 mA cm^–2, while baseline Cu prematurely fails when the current reaches 0.5 mA cm^–2. The half–cells cells of rGO@3D–Cu (no K reservoir) are stable at 0.5 mA cm^–2 for 10 000 min (100 cycles), and at 1 mA cm^–2 for 5000 min. The baseline 3D–Cu, planar rGO@Cu, and planar Cu foil fails after 5110, 3012, and 1410 min, respectively.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States). Center for Integrated Nanotechnologies (CINT)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; USDOE National Nuclear Security Administration (NNSA); USDOE Office of Electricity (OE)
• Grant/Contract Number: AC05-00OR22725; SC0018074; 89233218CNA000001
• OSTI ID: 1606027
• Alternate ID(s): OSTI ID: 1580157; OSTI ID: 1634976
• Report Number(s): LA-UR-19-32524
• Journal Information: Advanced Materials, Vol. 32, Issue 7; ISSN 0935-9648
• Publisher: WileyCopyright Statement
• Country of Publication: United States
• Language: English