High-performance battery electrodes via magnetic templating

In lithium-ion batteries, the critical need for high-energy-density, low-cost storage for applications ranging from wearable computing to megawatt-scale stationary storage has created an unmet need for facile methods to produce high-density, low-tortuosity, kinetically accessible storage electrodes. Here we show that magnetic control of sacrificial features enables the creation of directional pore arrays in lithium-ion electrodes. The directional pores result in faster charge transport kinetics and enable electrodes with more than threefold higher area capacity (for example, >12 mAh cm−2 versus <4 mAh cm−2 in conventional electrodes) at practical charge–discharge rates. We demonstrate these capabilities in laboratory cells under various test conditions, including an electric vehicle model drive cycle. Electrode materials with pores generally have high tortuosity, which is detrimental to battery performance. Here the authors develop a magnetic alignment approach that produces battery electrodes with low-tortuosity porosity and high capacity.