High Performance Voltage Tailorable Room-temperature Ca-metal Batteries

Abstract

Calcium metal battery as one of the promising alternatives beyond Li-metal technology is challenged by the lack of suitable cathodes with considerable energy performance, and stable Ca anode of long-term stability and lower polorization potentials for Ca-plating/stripping. Here, by recycling cellulose waste paper of wide sources in our daily life, we develop feasible cathodes for Ca-metal batteries of good high-voltage and wide-window-voltage adaptability (0.005-4.9 V vs. Ca/Ca2+), except for considerable energy performance (~517.5 Wh kg-1 at 0.1 A g-1). Meanwhile, through tailorable Ca-plating/stripping potentials (∆V= ~0.65 V) induced by electrolyte modification, proof-of-concept Ca-metal batteries not only delivered enhanced storage capability (101 mAh g-1 vs. 51 mAh g-1 at 0.1 A g-1 in the window voltage of 2.0-4.7 V ) and cycling stability (~77% capacity retention for 100 cycles), but also simutaneously held high output average working voltage of ~3.2V.