Semi-solid batteries — perhaps the ultimate route for electric vehicles

Factors driving the proliferation of lithium-ion batteries

Since Sony commercialised lithium-ion batteries in 1990, they have gained substantial market share. Compared with other energy storage devices, lithium-ion batteries have the advantages of high energy density and long cycle life.

Developing direction of lithium-ion batteries — solid-state lithium-ion batteries

To thoroughly address the safety issues, the use of highly flammable organic liquid electrolytes should be avoided entirely; all-solid-state batteries (ASSBs) become a good choice because organic liquid electrolytes are replaced by inorganic solid electrolytes that have high thermal stability.

  • Inorganic solid electrolytes have much better electrochemical stability than organic liquid electrolytes and polymer electrolytes, and are compatible with higher potential cathode materials to increase energy density.
  • ASSBs have excellent mechanical properties. [3]
  • Even if the technical problems are solved, the cost of production needs to be reduced before production of large volumes could start. The price of raw materials for solid-state lithium-ion batteries is currently five times more than that of raw materials for traditional lithium-ion batteries. Besides, production of solid-state lithium-ion batteries requires high purity of raw materials, which translates into significant investment in equipment. [5]

The semi-solid-state lithium-ion battery — the compromise

A semi-solid-state lithium-ion battery is a battery where one electrode contains liquid electrolytes while the other electrode contains no liquid electrolytes. From the view of percentage of weight, liquid electrolytes account for 20% of a traditional lithium-ion battery’s weight, but 10% of a semi-solid-state lithium-ion battery’s weight. [6]



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Acuity Knowledge Partners

Acuity Knowledge Partners


We write about financial industry trends, the impact of regulatory changes and opinions on industry inflection points.