(Invited) Recent Progress Towards Giga-Scale Sodium-Ion Batteries

Abstract

Ongoing lithium-ion minerals supply chain volatility has driven price increases and supply shortages, and motivates the development and commercialization of alternative cell chemistries not dependent on those minerals.1-2 Among these alternative chemistries, sodium-ion cells offer promise due to the abundance and low cost of both sodium salts and typical electrode active species such as iron and manganese.2-3 Among sodium-ion electrode systems, Prussian blue analogues offer unique performance advantages including high C-rate charge and discharge, long cycle life, and thermal stability.4-6 Natron Energy has commercialized a unique sodium-ion cell in which each of the anode and cathode active materials are Prussian blue analogues. Products based on these cells are capable of full discharge at up to 60C, full recharge at up to 20C, and operate for tens of thousands of cycles without risk of thermal runaway. However, their energy density is limited by relatively low electrode specific capacities and cell voltage. This presentation will introduce the key materials science concepts that make Prussian blues a commercially viable materials system, as well as those that limit product performance, manufacturability, and the resulting applicable markets. In addition, Natron’s recent progress towards mass manufacturing of cells based on these materials will be summarized. This presentation will conclude with an overview of the key open scientific questions that must be answered for cost effective, giga-factory scale manufacturing of sodium-ion cells to become a reality.