Layer-by-Layer Assembly of Strong Thin Films with High Lithium Ion Conductance for Batteries and Beyond

• Polyethylene oxide (PEO) is one of the most widely used polymeric ion conductors which has the potential for a wide range of applications in energy storage. The enhancement of ionic conductivity of PEO-based electrolytes is generally achieved by sacrificing the mechanical properties. Using layer-by-layer (LbL) self-assembly with a nanoscale precision, mechanically strong and self-healable PEO/polyacrylic acid composite thin films with a high Li+ conductivity of 2.3 ± 0.8 × 10−4 S cm−1 at 30 °C, and a strength of 3.7 MPa is prepared. These values make the LbL composite among the best recorded multifunctional solid electrolytes. The electrolyte thin film withstands at least 1000 cycles of striping/plating of Li at 0.05 mA cm−2. It is further shown that the LbL thin films can be used as separators for Li-ion batteries to deliver a capacity of 116 mAh g−1 at 0.1 C in an all-LbL-assembled lithium iron phosphate/lithium titanate battery. Finally, it is demonstrated that the thin films can be used as ion-conducting substrates for flexible electrochemical devices, including micro supercapacitors and electrochemical transistors.

Ämnesord

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

Nyckelord

ionic conduction

lithium-ion batteries

mechanical strength

self-assembly

Energy storage

Ions

Iron compounds

Lithium compounds

Nanocomposite films

Polyethylene oxides

Self assembly

Solid electrolytes

Thin film lithium ion batteries

Composite thin films

Electrochemical transistors

Electrolyte thin film

Layer by layer self assembly

Layer-by-layer assemblies

Lithium iron phosphates

Micro supercapacitors

Polyethylene oxide (PEO)

Thin films

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