Non-precious Metal Bifunctional Catalyst For Rechargeable Zinc-air Battery

This article mainly studies the design and preparation of rechargeable zinc-air battery energy storage devices based on non-precious metal catalysts.The following two tasks have been done:?1?In recent years,along with wearable microelectronic technology to flourish,the urgent need for compatible micro-power.They need to consider energy density,flexibility,and safety.Zinc-air battery with high theoretical capacity density and low risk,there is a great prospect in the new energy storage systems,further development of a compact solid-state rechargeable zinc-air batteries for wearable applications with the urgent need.Through the combination of inverse-opal-structured hybrids of N,S-codoped-carbon-confined Co₉S₈ nanoparticles for high-efficient bifunctional electrocatalysts at air-cathode and polyacrylamide-co-polyacrylic acid alkalinous hydrogel of high ion-conductivity and water holding power for solid electrolyte,on-chip all-solidstate rechargeable Zn-air batteries?OAR-ZABs?are developed.The OAR-ZABs acquire a higher open circuit potential of 1.408 V,larger specific capacity of 738 mA h g^-1,and better rechargeability?105 cycles/35 h?compared with most reported devices employing traditional PVA basic hydrogel electrolyte.The exhibited areal/specific energy densities(7.53 mW h cm^-2/900.4 Wh kg^-1)also outperform the values of competitors such as micro-supercapacitors(?0.01 mW h cm^-2)and Li-ion batteries(?200 Wh kg^-1).Furthermore,the reasonable in-plane electrode deployment endows the OAR-ZABs with good coplanar integration capability and high flexibility,allowing in-plane series/parallel connection to output required voltage/current and working stably at different bending angles.Combined with the other advantages including its miniaturization and the inherent security of employed hydrogel electrolyte,the OAR-ZABs are ideally suitable for wearable applications.As a demo,a flexible OAR-ZABs array in series connection is fabricated and conformally sewed on clothes,being safely used to charge the smart phone or light the safety warning device.All these make them competitive micropower sources for wearable microelectronics?2?The short cycle life of rechargeable zinc-air batteries is the main reason for limiting its large-scale promotion.The poor durability of bifunctional oxygen electrocatalysts and the corrosion of alkaline electrolytes on zinc electrodes are the main bottlenecks in suppressing the charge-discharge cycle of rechargeable metal-air batteries.Herein,Impregnating Co₉S₈ nanoparticles into defective carbon pores which act as interconnected nanoreactors.This design not only delivers a high surface-to-volume ratio to increase numbers of exposed catalytic sites,but also precludes nanoparticles from aggregation during cycling due to the pore spatial confinement effect.Therefore,the long-term trouble inherent to nanocatalyst stability can be solved.Consequently,the developed catalyst presents superior bifunctional oxygen electrocatalytic activities and durability.In addition,the use of conventional alkaline ZAB is severely restricted by corrosion and dendrite growth at the Zn anode and rapid carbonate formation of the electrolyte.Herein,we report an emerging type of ZAB that uses a near-neutral electrolyte?ZnCl₂-NH₄Cl?with high ionic conductivity;The ZAB system is more environmentally friendly and less corrosive than alkaline electrolytes,thus potentially avoiding carbonization problems and mitigating corrosion issues.In a practical application to rechargeable Zn-air batteries,long-term cyclability for over 1000 h is realized at a current density of 10 mA cm^-2 in ambient air,This technique works by engineering design and fabrication of nanostructures an efficient electrically non-noble metal catalysts,and the use of a stable electrolyte system,can effectively improve the cycle life of a rechargeable zinc-air cell.