While neutral aqueous metal batteries,featuring cost-effectiveness and non-flammability,hold significant potential for large-scale energy storage,their practical application is hampered by the limited specific capacit...While neutral aqueous metal batteries,featuring cost-effectiveness and non-flammability,hold significant potential for large-scale energy storage,their practical application is hampered by the limited specific capacity of cathode materials(<500 mAh g^(-1)).Herein,capacity-oriented CoS2 and rate-optimized Co9S8 cathodes are developed based on the aqueous copper ion system.The charge-storage mechanism is sys-tematically investigated through a series of ex-situ tests and density functional theory calculations,fo-cusing on the reversible transitions of Co9S8→Cu7S4→Cu9S5/Cu1.8S and CoS2→Cu7S4→Cu2S,which are associated with the redox reactions of Cu^(2+)/Cu^(+)‖Co^(2+)/Co and Cu^(2+)/Cu^(+)‖S22-/S2-,respectively.The elec-trochemical results show that CoS2 can exhibit a superior capacity of 619 mAh g^(-1) at 1 A g^(-1) after 400 cycles,while Co9S8 maintains an outstanding rate performance of 497 mAh g^(-1) at 10 A g^(-1)(the retention rate is 95%compared to 521 mAh g1 at 1 A g^(-1)).As a proof of concept,an advanced CoS2//Zn hybrid aqueous battery demonstrates a working voltage of 1.20 V and a specific energy of 663 Wh kgcathode-1.This work provides an alternative direction for developing sulfide cathodes in energetic aqueous metal batteries.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52301282 and 52072256)Shanxi Province Science and Technology Program Unveiled Bidding Program(No.20201101016)+2 种基金Key Research and Development Program of Shanxi Province(Nos.202102030201006 and 202202070301016)Central Guidance for Local Science and Technology Development Funds Program(No.YDZJSX2021B005)Science and Technology Innovation Base Construction Program of Shanxi Province(No.YDZJSX2022B003).
文摘While neutral aqueous metal batteries,featuring cost-effectiveness and non-flammability,hold significant potential for large-scale energy storage,their practical application is hampered by the limited specific capacity of cathode materials(<500 mAh g^(-1)).Herein,capacity-oriented CoS2 and rate-optimized Co9S8 cathodes are developed based on the aqueous copper ion system.The charge-storage mechanism is sys-tematically investigated through a series of ex-situ tests and density functional theory calculations,fo-cusing on the reversible transitions of Co9S8→Cu7S4→Cu9S5/Cu1.8S and CoS2→Cu7S4→Cu2S,which are associated with the redox reactions of Cu^(2+)/Cu^(+)‖Co^(2+)/Co and Cu^(2+)/Cu^(+)‖S22-/S2-,respectively.The elec-trochemical results show that CoS2 can exhibit a superior capacity of 619 mAh g^(-1) at 1 A g^(-1) after 400 cycles,while Co9S8 maintains an outstanding rate performance of 497 mAh g^(-1) at 10 A g^(-1)(the retention rate is 95%compared to 521 mAh g1 at 1 A g^(-1)).As a proof of concept,an advanced CoS2//Zn hybrid aqueous battery demonstrates a working voltage of 1.20 V and a specific energy of 663 Wh kgcathode-1.This work provides an alternative direction for developing sulfide cathodes in energetic aqueous metal batteries.
