New simulations reveal how tiny carbon pores can boost next wave of sodium batteries

A new study from Brown University provides critical insights into how sodium ions behave within porous carbon structures, advancing the development of sodium-ion battery anodes. Sodium-ion batteries are promising alternatives to lithium-ion batteries due to sodium’s abundance, lower cost, and reduced environmental impact. However, progress has been hindered by uncertainties around the optimal anode material. The research focuses on hard carbon, the leading candidate for sodium-ion anodes, whose microscopic structure and sodium storage mechanism have been poorly understood and widely debated. Using zeolite-templated carbon with precisely controlled nanopores and advanced simulations, the study reveals a two-step sodium storage process inside carbon pores about one nanometer in size. Sodium atoms first form ionic bonds lining the pore walls, then accumulate as metallic clusters in the pore center. This dual ionic-metallic behavior is key to maintaining low anode voltage and preventing harmful metal plating, which can cause battery short circuits. These findings establish concrete design specifications for hard carbon anodes, enabling targeted synthesis of materials