UCLA team uses graphite to boost performance of lithium iron phosphate cathode materials
03 March 2021
Lithium iron phosphate (LiFePO4) is widely used as a low-cost, safer cathode material for Li-ion batteries; however, low ionic and electronic conductivity limit its rate performance.
Now, researchers at UCLA have synthesized LiFePO4/graphite composites in which LiFePO4 nanoparticles are grown within a graphite matrix. The graphite matrix is porous, highly conductive, and mechanically robust, giving the resulting electrodes outstanding cycle performance and high rate capability.
In a paper in the ACS journal Nano Letters, the team reports achieving high-mass-loading electrodes with high reversible capacity (160 mAh g–1 under 0.2 C), ultrahigh rate capability (107 mAh g–1 under 60 C), and outstanding cycle performance (>95% reversible capacity retention over 2000 cycles).
The composite material can lead to electrodes with volumetric energy density as high as 427 Wh L–1 under 60 C—of great interest for electric vehicles and other applications.
The approach provides a new strategy toward low-cost, long-life, and high-power batteries, the researchers concluded.
Resources
Fan Li, Ran Tao, Xinyi Tan, Jinhui Xu, Dejia Kong, Li Shen, Runwei Mo, Jinlai Li, and Yunfeng Lu (2021) “Graphite-Embedded Lithium Iron Phosphate for High-Power–Energy Cathodes” Nano Letters doi: 10.1021/acs.nanolett.1c00037
This means LFP can charge faster.
Posted by: SJC | 03 March 2021 at 10:48 AM
This means hybrids are becoming a no-brainer. 60 C performance means 90 kW out of 1.5 kWh of cells, more than enough to propel a vehicle engine-off.
Posted by: Engineer-Poet | 03 March 2021 at 11:53 AM
Tesla recently announced LiFePO4 batteries would be used in the lower range trim of the '3' model and as a replacement for their 12 volt lead acid batteries, used in all their cars. Conjecture is they will also use it in their upcoming $25k car.
UCLA's timing is very good to announce possible improvements for this chemistry. Perhaps this can lead to a large U.S. LiFePO4/C battery Business and the need to import less batteries from China.
Posted by: Lad | 03 March 2021 at 06:22 PM
Seems like hybrids with 15-25 kwh and a really small, simple, cheap ICE with direct drive for highway only would be a best cost balance.
1.5kwh is only $150-$250 worth of battery to power a much more expensive e-motor, and only cover very limited range. 15-25 kwh would cover 90% or more of mileage.
Posted by: GdB | 04 March 2021 at 12:51 PM
The purpose of the tiny battery is to make something like the Nissan e-POWER possible at minimum cost. You can keep adding battery, but that also adds weight, bulk and cost; you don't need them if you can charge at 60 C. You get the benefit of the efficiency gains right off the bat; the customer can decide what the best tradeoffs are for the rest.
Posted by: Engineer-Poet | 04 March 2021 at 02:55 PM