Fig. 4: Galvanostatic charge–discharge tests of SSBs applying different upper cutoff voltage.

Charge–discharge curves of the a 1st and b 100th cycle. c Capacity retention and d voltage hysteresis of four cells in 100 cycles. The capacity retention in c is normalized with the corresponding discharge capacity of 1st cycle. The voltage hysteresis in d is calculated with the difference of average charge/discharge voltage.