This requires thick electrodes performing at near-theoretical specific capacity.
However, achievable electrode thicknesses are restricted by mechanical instabilities, with high-thickness performance limited by the attainable electrode conductivity.
The researchers showed that forming a segregated network composite of carbon nanotubes with a range of lithium storage materials (for example, silicon, graphite and metal oxide particles) suppresses mechanical instabilities by toughening the composite, allowing the fabrication of high-performance electrodes with thicknesses of up to 800 μm.
Such composite electrodes display conductivities up to 1 × 104 S/m and low charge-transfer resistances, allowing fast charge-delivery and enabling near-theoretical specific capacities, even for thick electrodes.
The combination of high thickness and specific capacity leads to areal capacities of up to 45 and 30mAh/cm2 for anodes and cathodes, respectively.
Combining optimised composite anodes and cathodes yields full cells with state-of-the-art areal capacities (29mAh/cm2) and specific/volumetric energies (480Wh/kg and 1,600Wh/litre).
“Thee combination of Nokia Bell Labs’ device knowledge and AMBER’s materials science expertise allowed us to tackle an extremely difficult problem involving multiple disciplines,” says Nokia’s Paul King (pictured).
“Amber’s partnership with Nokia Bell Labs through their Distinguished Academic Partners Program has been a hugely positive experience,” says Amber’s Dr Lorraine Byrne.