Scalable Synthesis of Solid-State Electrolytes Using Flame-Assisted Spray Pyrolysis
As the impacts of climate change become more apparent, demands for reliable and safe energy storage options are rapidly increasing. The decarbonization of several sectors that are responsible for large amounts of annual greenhouse gas emissions, such as the electricity and transportation sectors, ca...
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| Format: | Thesis |
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Massachusetts Institute of Technology
2022
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| Online Access: | https://hdl.handle.net/1721.1/144979 https://orcid.org/ 0000-0003-4859-252X |
| Summary: | As the impacts of climate change become more apparent, demands for reliable and safe energy storage options are rapidly increasing. The decarbonization of several sectors that are responsible for large amounts of annual greenhouse gas emissions, such as the electricity and transportation sectors, can significantly benefit from improved energy storage options. In recent decades, lithium-ion batteries (LIBs) have become a prominent contender for storing energy in a variety of applications. However, the safety, lifespan, power capability, and energy density need to improve in order for LIBs to be adopted on a wider scale. Unfortunately, LIB technology is reaching its performance limits due to the inclusion of a flammable liquid electrolyte. One solution being considered to improve LIB performance is to replace the liquid electrolyte with a non-flammable solid-state electrolyte (SSE), which enables the use of high voltage cathode materials and a lithium metal anode, thereby greatly improving the power and energy density of the battery. Of the various chemistries being considered for solid-state electrolytes, oxide-based SSEs are advantageous due to their safety and electrochemical and thermal stability. To ensure good rate performance and energy density, oxide-based SSEs must be manufactured in a thin, dense format. However, many current methods used to synthesize oxide-based SSEs are either too expensive and complex or produce powders that require many post-processing steps, which precludes the commercialization of oxide-based SSEs. In this work, flame-assisted spray pyrolysis (FASP), an inexpensive, scalable synthesis method, was used to produce SSE powders which can be further processed to fabricate thick pellet or thin-tape solid-state electrolyte samples. Li6.25Al0.25La3Zr2O12 (Al-doped LLZO) was synthesized due to its impressive electrochemical stability and relatively high ionic conductivity. The effect of FASP parameters on the as-synthesized Al-doped LLZO powder and on the quality of pellets and thin-tapes was investigated, and a stand-alone, all-oxide-based SSE having a total ionic conductivity of 3.5 x 10-6 S/cm was synthesized. The results show that FASP parameters can be tailored to produce solid-state electrolytes in an inexpensive, scalable way. |
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