MOF‐Derived CoSe <sub>2</sub> Nanoparticles/Carbonized Melamine Foam as Catalytic Cathode Enabling Flexible Li–CO <sub>2</sub> Batteries with High Energy Efficiency and Stable Cycling
Ke Wang, Limin Liu, Dongyu Liu, Yuantao Wei, Yanxia Liu, Xinqiang Wang, Andrey S. Vasenko, Mingtao Li, Shujiang Ding, Chunhui Xiao, Hongge Pan
Abstract
Abstract Rechargeable aprotic Li–CO 2 batteries have aroused worldwide interest owing to their environmentally friendly CO 2 fixation ability and ultra‐high specific energy density. However, its practical applications are impeded by the sluggish reaction kinetics and discharge product accumulation during cycling. Herein, a flexible composite electrode comprising CoSe 2 nanoparticles embedded in 3D carbonized melamine foam (CoSe 2 /CMF) for Li–CO 2 batteries is reported. The abundant CoSe 2 clusters can not only facilitate CO 2 reduction/evolution kinetics but also serve as Li 2 CO 3 nucleation sites for homogeneous discharge product growth. The CoSe 2 /CMF‐based Li–CO 2 battery exhibits a large initial discharge capacity as high as 5.62 mAh cm −2 at 0.05 mA cm −2 , a remarkably small voltage gap of 0.72 V, and an ultrahigh energy efficiency of 85.9% at 0.01 mA cm −2 , surpassing most of the noble metal‐based catalysts. Meanwhile, the battery demonstrates excellent cycling stability of 1620 h (162 cycles) at 0.02 mA cm −2 with an average overpotential of 0.98 V and energy efficiency of 85.4%. Theoretical investigations suggest that this outstanding performance is attributed to the suitable CO 2 /Li adsorption and low Li 2 CO 3 decomposition energy. Moreover, flexible Li–CO 2 pouch cell with CoSe 2 /CMF cathode displays stable power output under different bending deformations, showing promising potential in wearable electronic devices.