A New Secondary Battery Based on Carbonate Anion Shuttling in Aqueous Alkaline Electrolyte

ABSTRACT Aqueous secondary batteries (ASBs) employing CO ₃ ²⁻ electrolyte are rare‐studied but desirable technologies providing eco‐friendly, safe, and cost‐effective energy storage. Herein, novel ASBs based on CO ₃ ²⁻ anion shuttling between CoNiCu‐C‐LDH/CNT and Cu ₂ CO ₃ (OH) ₂ /CNT in alkaline electrolyte (AACBs) are reported for the first time. During charge/discharge, Co/Ni metals in laminates of cathode subjected to oxidation/reduction while CO ₃ ²⁻ is reversibly inserted/extracted within interlayers, juxtaposed with CO ₃ ²⁻ released/consolidated on anode. Integrated into pouch battery, highly reversible electrochemical properties were discovered, powering 2 white LEDs with two AACBs in tandem. The initial capacity at 200 mA g ⁻¹ was ∼130 mAh g ⁻¹ with stable retention of ∼101 mAh g ⁻¹ after 200 cycles. At 400/800 mA g ⁻¹ , capacities of ∼94/∼67 mA g ⁻¹ were marked respectively. The AACBs hold lowest energy cost, enabling massive production. The excellent CO ₃ ²⁻ storage can also be reached via Cl ⁻ transporting. The findings highlight potential of LDHs on sustainable energy storage/conversion, identifying promising development prospects to new class of aqueous anion batteries (AABs).