Electrode Insights Could Boost Battery Capacity

Electrode Insights Could Boost Battery Capacity

May 02, 2019

New research from Lawrence Berkeley National Lab (Berkeley Lab) opens up new possibilities for packing more energy into batteries with electrodes made out of low-cost, common materials.

Advanced spectroscopy at the ALS clearly resolves the activities of cations and anions (known in Chinese as “yin” and “yang” ions) in battery electrodes.The study focused on the rechargeable batteries we depend on for everything from mobile phones to electric vehicles. A team of scientists quantified a strong, beneficial, and highly reversible chemical reaction involving oxygen ions in the crystal lattice of battery electrode materials.

The researchers were examining lattice oxygen, or oxygen that is part of a crystal lattice structure in a battery electrode, rather than present on the surface. Oxygen can boost battery capacity, but conventional wisdom held that introducing oxygen can harm the reversibility of the chemical reactions, which is key to commercial viability.

The researchers fabricated and tested a sodium-ion battery material using manganese, an abundant metal, and found that a very strong lattice-oxygen redox reaction accounted for most of the battery’s capacity. Surprisingly, this strong reaction did not compromise reversibility: 87 percent of the capacity was retained after 100 charge-discharge cycles. The study settles the debate about the reversibility of lattice-oxygen redox in battery electrodes made of common elements. 

The research team included Gao Liu, who leads the Applied Energy Materials Group within Berkeley Lab’s Energy Technologies Area, and was performed using the Advanced Light Source. Read more about the research here.