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R&D Focus

ChemSEI-Linker Enhances Lithium Battery Life

Video of ChemSEI-Linker.

Among various green technologies that can reduce carbon emissions, electric vehicles (EVs) have become a main solution. Many countries endeavor to develop high-capacity, long-life, and low-cost lithium-ion batteries for EVs. However, the current technology for large-scale lithium-ion battery production lacks adequate technical maturity, and it is too expensive. Therefore, numerous factories produce batteries with limited functionality, small capacity, and insufficient endurance. ITRI’s ChemSEI-Linker is an artificial nanoscale solid electrolyte interface of unique composition and structure that stabilizes lithium battery electrodes, increasing battery life by up to 100%.

The ChemSEI-Linker Battery.

The ChemSEI-Linker Battery.

Lithium nickel cobalt aluminum oxide battery, or NCA, is currently an attractive option for vehicular applications due to its high specific capacity (180–200 mAh/g) and high power capability (680–760 Wh/kg); yet it is not considered to be inherently safe and cost-effective. In view of this, ITRI’s team developed both a self-forming chemical solid electrolyte interface (ChemSEI) modification technology and an electrode paste with linker called Chemlinkbat paste. These two technologies are integrated into a unique, multifunctional architecture called ChemSEI-Linker (See the figure below).

Self-forming ChemSEI-Linker and Chemlinkbat electrodes.

Self-forming ChemSEI-Linker and Chemlinkbat electrodes.

ChemSEI-Linker produces a high-quality and stable structure with strong adhesion on the surfaces of the cathode and anode materials of various types of lithium-ion batteries. This protects the active electrode materials from being attacked and damaged by the electrolyte, and reduces the cumulative electrochemical damage of the SEI film. ChemSEI-Linker may enhance the operating voltage range for the electrode materials, and thus may improve the battery capacity by 15%; it may also increase the service life of a lithium-ion battery by more than 70%. In particular, the use of ChemSEI-Linker with a high-voltage design may enable a Tesla Model S battery to increase its endurance from 480 km to more than 550 km and may extend the battery service life beyond 3,000 charge/discharge cycles.

In addition, because the active electrode material is protected by the ChemSEI-Linker layer, the charge/discharge cycle does not produce microcracks, allowing a manufacturer to extract the undamaged material for direct reuse. This helps streamline recycling operations and reduces costs.

Compared to existing products for 18650 cells, ITRI’s cell is superior in many areas: it has wider operating voltage and longer service life, exhibiting higher safety as it passes nail penetration tests; moreover, its electrode material can be directly recycled. When compared to prismatic batteries, ITRI’s product outperforms the others in terms of higher energy density, longer cycle life, higher safety, and the direct recyclability of electrode material. Detailed comparisons are shown in the following table.

Comparison of ITRI’s ChemSEI-Linker Battery and Existing Products.
18650-Type ITRI’s ChemSEI-Linker Battery Brand P Brand S
Capacity (mAh) 3,050 3150 2950
Nominal Voltage (V) 3.7 3.7 3.8
Operating Voltage (V) 2.5-4.35 2.5~4.2 2.75~4.35
Cycle Life Remaining 80% of capacity [0.5C (4.2V)/1C (2.5V)] > 1,000 < 300 < 300
Safety Nail Penetration Test V X X
Recyclability Initial Cathode Material V X X
Prismatic-Type ITRI’s ChemSEI-Linker Battery Brand S Brand D
Capacity (Ah)-Ternary System 48 60 50
Energy Density (Wh/kg) 160 125 130
Cycle Life Remaining 80% of Capacity [1C1/1C-100% DOD] > 3,000 1,400 2,000
Safety Nail Penetration Test V X X
Recyclability Initial Cathode Material V X X

ChemSEI-Linker improves battery electrode materials by including structural flexibility and stability, efficient protection for battery safety, and recycling performance. The transport mechanisms for electrons and ions enhance the internal resistance levels of battery electrodes. The surface structures and surface properties of various materials, such as organic hyperbranched polymers, linkers, conduction materials, inorganic ion-conduction materials, binders, and additives all have fundamental differences. Major applications of ChemSEI-Linker battery include smart wearables, EVs, robots, energy storage systems, and many other products.