Rechargeable Room‐Temperature Na–CO2 Batteries

Abstract

Developing rechargeable Na–CO₂ batteries is significant for energy conversion and utilization of CO₂. However, the reported batteries in pure CO₂ atmosphere are non-rechargeable with limited discharge capacity of 200 mAh g⁻¹. Herein, we realized the rechargeability of a Na–CO₂ battery, with the proposed and demonstrated reversible reaction of 3 CO₂+4 Na↔2 Na₂CO₃+C. The battery consists of a Na anode, an ether-based electrolyte, and a designed cathode with electrolyte-treated multi-wall carbon nanotubes, and shows reversible capacity of 60000 mAh g⁻¹ at 1 A g⁻¹ (≈1000 Wh kg⁻¹) and runs for 200 cycles with controlled capacity of 2000 mAh g⁻¹ at charge voltage 2.