Cross-linked K 0.5 MnO 2 nanoflower composites for high rate and low overpotential Li-CO 2 batteries.

Rechargeable Li-CO 2 batteries are deemed to be attractive energy storage systems, as they can effectively inhale and fix carbon dioxide and possess an extremely high energy density. Unfortunately, the irreversible decomposition of the insoluble and insulating Li 2 CO 3 results in awful electrochemical performance and inferior energy efficiency of Li-CO 2 batteries. Furthermore, the low energy efficiency will exacerbate the extra waste of resources. Therefore, it is vital to design novel and efficient catalysts to enhance the battery performance. Herein, a facile, one-step strategy is introduced to design cross-linked, ultrathin K 0.5 MnO 2 nanoflowers combined with CNTs (K 0.5 MnO 2 /CNT) as a highly efficient cathode for Li-CO 2 batteries. Impressively, the Li-CO 2 battery based on the K 0.5 MnO 2 /CNT cathode achieves a low overpotential (1.05 V) and a high average energy efficiency (87.95%) at a current density of 100 mA g -1 . Additionally, the K 0.5 MnO 2 /CNT cathode can steadily run for over 100 cycles (overpotential < 1.20 V). Moreover, a low overpotential of 1.47 V can be obtained even at a higher current density of 1000 mA g -1 , indicating the superior rate performance of K 0.5 MnO 2 /CNT. This strategy offers new insight and guidance for the development of low-cost and high-performance Li-CO 2 batteries.