Electrochemical formation protocols for maximising the life-time of a sodium ion battery†
Electrochemical protocols for reducing formation time and maximising cycle life in a sodium ion battery are proposed. The formation protocols comprise low current cycles within a targeted voltage window. After accelerated cell aging tests, the impedance and cycle life are evaluated. Maximum life time is obtained for formation within the 3.6–3.8 V window. 250 cycles are observed to 80% of initial capacity with accelerated ageing, compared to 90 cycles with no formation.