|Argonne’s patented composite cathode materials (xLi2MnO3·(1-x)LiMO2) offer a good blend of safety, capacity and cost, according to BASF. Source: Argonne. Click to enlarge.|
The US Department of Energy’s (DOE) Argonne National Laboratory and BASF have signed a world-wide licensing agreement to mass produce and market Argonne’s patented composite cathode materials to manufacturers of advanced lithium-ion batteries. BASF will conduct further lithium-ion battery material application development in its current Beachwood, Ohio facility.
Contingent upon winning a DOE grant under Recovery Act - Electric Drive Vehicle Battery and Component Manufacturing Initiative (DE-FOA-0000026), BASF plans to build one of North America’s largest cathode material production facilities in Elyria, Ohio.
The exact scope of the materials included in the licensing deal with Argonne is confidential, according to Dr. Prashant Chintawar, Senior Manager of BASF Future Business NA, but does include formulations from the Argonne patented xLi2MnO3·(1-x)LiMO2 (M= Mn, Ni, Co) structures (also called NMC). An electrochemically inactive Li2MnO3 component integrated with an electrochemically active LiMO2 component provides improved structural and electrochemical stability at high potentials.
In some formulations, the Argonne NMC materials can provide an initial capacity of > 250 mAh g-1 when discharged between 5 and 2.0V and a rechargeable capacity of up to 250 mAh g-1 over the same window. Argonne also licensed these composite materials to Toda Kogyo Corp. of Japan in 2008. (Earlier post.)
The combination of lithium and manganese rich mixed metal oxides extends the operating time between charges, increases the calendar life and improves the inherent safety of lithium-ion cells. Moreover, the enhanced stability of the composite material permits battery systems to charge at higher voltages, which leads to a substantially higher energy storage capacity than currently available material through both the higher voltage and higher capacity per unit weight of active material.
Based on customer feedback, according to Dr. Chintawar, BASF believes these NMC formulations can offer the right combination of safety, capacity and cost to serve as the next generation of dominant cathode material in the evolving Li-ion market. Lithium cobalt oxide materials, he noted, introduced in 1991, still have a more than 60% market share. BASF plans to commercialize these new cathode materials for transportation and other applications.
Known issues with the current composite materials, said Argonne’s Dr. Michael Thackeray during the DOE 2009 merit review meetings, include a large irreversible capacity loss on the initial cycle. Furthermore, charging high-capacity xLi2MnO3•(1-x)LiMO2 electrodes to a high potential (>4.4 V) damages the electrode surface and reduces the rate capability of the electrode.
Improving the rate capability of high-capacity composite electrodes particularly at room temperature is still required to meet the 40-mile range battery requirement for plug-in hybrids, Thackeray said. Ongoing work at Argonne is seeking ways to stabilize the surfaces of the composite electrodes. Flourination is one approach that is promising (earlier post), and phosphate stabilization is another pathway of interest, he noted.
Future work at Argonne in this area will continue to exploit and optimize the xLi2MnO3•(1-x)LiMO2electrodes (composition and performance) with the particular goal of reaching or exceeding the energy and power goals required for 40-mile PHEVs and EVs.
There will be a focus on surface studies, using both fluorides and phosphates to improve stability and rate capability of metal oxide electrodes at high potentials.
BASF is contemplating a research collaboration with Argonne, Chintawar said.
BASF Future Business GmbH, a 100% subsidiary of BASF SE, was founded in April 2001 and owns the company’s lithium-ion battery portfolio, including the longer-term, more speculative work on lithium-sulfur batteries announced in May. (Earlier post.)
BASF currently offers a high-energy Lithium Nickel Cobalt Oxide (LNCO) cathode material.