Fast Lithium-Ion Conducting Thin-Film Electrolytes Integrated Directly on Flexible Substrates for High-Power Solid-State Batteries
✍ Scribed by Jon F. Ihlefeld; Paul G. Clem; Barney L. Doyle; Paul G. Kotula; Kyle R. Fenton; Christopher A. Apblett
- Publisher
- John Wiley and Sons
- Year
- 2011
- Tongue
- English
- Weight
- 902 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0935-9648
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✦ Synopsis
A higher power, thin-fi lm lithium-ion electrolyte has been developed on copper substrates, aimed at mass-produced solid-state lithium batteries. Utilizing a high-temperature thermodynamic equilibrium processing strategy that enables co-fi ring of oxides and base metals, we present a means to integrate the crystalline, lithium-stable, fast lithium-ion conductor lanthanum lithium tantalate (La 1/3-x Li 3 x TaO 3 ) directly with a thin copper foil current collector appropriate for a lithium-free solid-state battery. This approach, marrying integration strategies conventional to capacitor technologies with a fast lithium-ion conductor, results in a thin fi lm electrolyte with a room temperature lithium-ion conductivity of 1.5 × 10 -5 S cm -1 , which holds the potential to increase the power of a solid-state battery by ca. 15 times compared to the current state of the art.
High lithium-ion conductivity thin-fi lm electrolytes for solidstate lithium-ion batteries are desired for reduced package size, increased safety, and enhanced power and energy density. There have been extensive efforts to develop solid-state lithiumion conductors appropriate for integration as electrolytes, including several candidate materials possessing room temperature ionic conductivities of up to 10 -3 S cm -1 . [ 1 ] In spite of these high reported conductivity values, many of these compositions suffer from issues that prevent their use in lithium-ion cells. For example, (Li,La)TiO 3 and Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 both display high ionic conductivities but are unstable in contact with lithium metal due to facile Ti 4 + reduction. [ 1 , 2 ] Thio-LISICON compositions of the general formula Li x M 1-y M ´ y S 4 ( M = Si, Ge, and M ´ = P, Al, Zn, Ga, or Sb) have shown great promise as high-conductivity solid electrolytes, [ 3 ] however these compositions do not cycle well with lithium metal anodes. [ 4 ] Owing to its stability in contact with lithium, ease of manufacture, and outstanding cyclability, the most widely used solid electrolyte fi lms are based on amorphous lithium phosphorus oxy-nitride (LiPON) compositions. [ 5 ] In this system modest room temperature ionic conductivities of ca. 10 -6 S cm -1 can be achieved through processing conditions compatible with many packaging embodiments. [ 6 ] In spite of the success and widespread use of LiPON in thin fi lm solid-state batteries, there is still a strong www.advmat.de www.MaterialsViews.com