Xidian University: indium-polysiloxane lithium coating retains 82.3% capacity over 300 cycles in lab cells
A one-step solution-cast layer on lithium metal protected the interface with a sulfide electrolyte in laboratory cells, raising critical current density to 3.5 mA cm⁻².
Researchers at Xidian University in China, led by Siwu Li, Weiwei Wu and Chuang Yu, have described a protective coating for lithium-metal anodes in all-solid-state batteries with a sulfide electrolyte. The work was published in Science China Chemistry (dx.doi.org, DOI 10.1007/s11426-026-3450-y). The indium-polysiloxane hybrid layer is grown directly on the lithium surface in a single solution-cast step. In laboratory cells, symmetric cells with the coated lithium sustained a critical current density of 3.5 mA cm⁻² dx.doi.org
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How the hybrid layer forms
The weak point of sulfide-based lithium-metal batteries is the sulfide/Li interface, where poor chemical matching and mechanical failure limit practical use dx.doi.org
dx.doi.orgdx.doi.orgOpen source ↗. In the proposed approach, In³⁺ salt and the fluorine- and silicon-containing groups of the polysiloxane are co-reduced on lithium. This produces inorganic nanodomains of LiF, In/LiIn and LiSiₓOᵧ inside the polymer network (PFSIn-Li)
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According to the authors, the layer is chemically inert to the Li₅.₅PS₄.₅Cl₁.₅ (LPSC) electrolyte and mechanically resistant to dendrite penetration. The press release states that the film is 12 micrometers thick. X-ray diffraction and photoelectron spectroscopy showed siloxane networks together with crystalline lithium fluoride, metallic indium and a lithium-indium alloy. Cross-sectional electron microscopy showed a dense, uniform film without cracks or gaps.
Cell test results
In symmetric cells, the coated lithium reached a critical current density of 3.5 mA cm⁻². The release gives 0.8 mA cm⁻² for unprotected lithium, so the value is more than four times higher dx.doi.org
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Full cells were built from coated lithium, the LPSC electrolyte and a LiNi₀.₇Co₀.₁Mn₀.₂O₂ cathode. At 0.5 C they delivered 129.8 mA h g⁻¹ in the first cycle and retained 82.3% of that capacity after 300 cycles. Cells with bare lithium retained 43.0% dx.doi.org
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The authors describe the chemistry as scalable and low-cost, and say the liquid coating could be applied with slot-die or gravure methods without vacuum equipment. The data reported so far come from laboratory cells.
