Developing efficient systems for
the conversion of carbon dioxide
to valuable chemicals using solar power is critical for mitigating
climate change and ascertaining the world’s future supply of
clean fuels. Here, we introduce a mesoscopic cathode consisting of
Cu nanowires decorated with Ag islands, by the reduction of Ag-covered
Cu2O nanowires prepared via galvanic replacement reaction.
This catalyst enables CO2 reduction to ethylene and other
C2+ products with a faradaic efficiency of 76%. Operando
Raman spectroscopy reveals intermediate formation of CO at Ag sites
which undergo subsequent spillover and hydrogenation on the Cu nanowires.
Our Cu–Ag bimetallic design enables a ∼95% efficient spillover
of intermediates from Ag to Cu, delivering an improved activity toward
the formation of ethylene and other C2+ products. We also demonstrate
a solar to ethylene conversion efficiency of 4.2% for the photoelectrochemical
CO2 reduction using water as electron and proton donor,
and solar power together with perovskite photovoltaics to drive the
uphill reaction.
Introduction
of inorganic solid electrolytes is believed to be an ultimate strategy
to dismiss dendritic Li in high-energy Li-metal batteries (LMBs),
and garnet-type Li7La3Zr2O12 (LLZO) electrolytes are impressive candidates. However, the current
density for stable Li plating/stripping in LLZO is still quite limited.
Here, we create in situ formed Li-deficient shields by the high-temperature
calcination at 900 °C. By this novel process, the formation of
Li2CO3 on LLZO is restrained, and then we successfully
obtain Li2CO3-free LLZO after removing the Li-deficient
compounds. Without any surface modification, Li2CO3-free LLZO shows an intrinsic “lithiophilicity”
characteristic. The contact angles of metallic Li on LLZO garnets
are assessed by the first-principle calculation to confirm the lithiophilicity
characteristic of LLZO electrolytes. The wetting of metallic Li on
the Li2CO3-free LLZO surface leads to a continuous
and tight Li/LLZO interface, resulting in an ultralow interfacial
resistance of 49 Ω cm2 and a homogeneous current
distribution in the charge/discharge processes of LMBs. Consequently,
the current density for the stable Li plating/stripping in LLZO increases
to 900 μA cm–2 at 60 °C, one of the highest
current density for LMBs based on garnet-type LLZO electrolytes. Our
findings not only offer insight into the lithiophilicity characteristics
of LLZO electrolytes to suppress dendritic Li at high current densities
but also expand the avenue toward high-performance, safe, and long-life
energy-storage systems.
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