Micron-sized single-crystal cathodes for sodium-ion batteries

Venkat Pamidi; Shivam Trivedi; Santosh Behara; Maximilian Fichtner; M Anji Reddy

doi:10.1016/j.isci.2022.104205

Micron-sized single-crystal cathodes for sodium-ion batteries

iScience. 2022 Apr 4;25(5):104205. doi: 10.1016/j.isci.2022.104205. eCollection 2022 May 20.

Authors

Venkat Pamidi¹, Shivam Trivedi¹, Santosh Behara², Maximilian Fichtner^{1

3}, M Anji Reddy²

Affiliations

¹ Helmholtz Institute Ulm (HIU) Electrochemical Energy Storage, Helmholtzstraße 11, 89081 Ulm, Germany.
² Faculty of Science and Engineering, Swansea University, Fabian Way, Swansea SA1 8EN, UK.
³ Institute of Nanotechnology, Karlsruhe Institute of Technology, PO. Box 3640, 76021 Karlsruhe, Germany.

Abstract

Confining the particle-electrolyte interactions to the particle surface in electrode materials is vital to develop sustainable and safe batteries. Micron-sized single-crystal particles offer such opportunities. Owing to the reduced surface area and grain boundary-free core, particle-electrolyte interactions in micron-sized single-crystal particles will be confined to the particle surface. Here, we reveal the potential of such materials in sodium-ion batteries. We synthesized and investigated the chemical, electrochemical, and thermal properties of single-crystalline P2-type Na_0.7Mn_0.9Mg_0.1O₂ as a cathode material for sodium-ion batteries. Single-crystalline Na_0.7Mn_0.9Mg_0.1O₂ with a mean particle size of 8.1 μm exhibited high cycling and voltage stability. In addition, the exothermic heat released by the charged single-crystal Na_0.7Mn_0.9Mg_0.1O₂ cathodes was four times lower than that of the corresponding polycrystalline Na_0.7Mn_0.9Mg_0.1O₂. This significantly enhances the thermal stability of electrode materials and possibly mitigates thermal runaways in batteries. Surprisingly, single crystals of Na_0.7Mn_0.9Mg_0.1O₂ were relatively stable in water and ambient atmosphere.

Keywords: Electrochemistry; Energy systems; Materials science.