With advantages of low costs and high energy density,Li–S batteries are considered as one of the most promising energy storage devices.However,Li_(2)S_(2) with a high dissociation energy and insulative properties is ...With advantages of low costs and high energy density,Li–S batteries are considered as one of the most promising energy storage devices.However,Li_(2)S_(2) with a high dissociation energy and insulative properties is hard to convert into Li_(2)S,resulting in underutilization of sulfur capacity.Herein,Co-Mo_(2)C@C yolk–shell spheres as nanoreactors were designed to confront this challenge rationally.The Co-Mo_(2)C@C-induced Li_(2)S_(1/2) nucleation and growth in the three-dimensional process and the cathode produced more Li_(2)S after full discharge.Experimental studies and theoretical calculations reveal that the conversion barrier from Li_(2)S_(2) into Li_(2)S was lowered while the diffusion of lithium ions and electron transfer accelerated when using the Co-Mo_(2)C@C catalyst.Based on the above advantages,the Co-Mo_(2)C@C/S cathode exhibits a high reversible capacity and excellent cyclic stability,such as an initial specific capacity of 1200 mAh g^(−1) at 0.1 C with 709 mAh g^(−1) at 1.0 C after 1000 cycles with a low capacity fading rate of 0.04%per cycle.Even at high densities of 3.0 C and 5.0 C,the specific capacities are 647.6 and 557.7 mAh g^(−1) after 400 cycles,respectively.Impressively,it also shows ca.770 and 900 mAh g^(−1) at 0.2 C after 50 cycles with high sulfur loadings of 4.2 and 5.1 mg cm−2,respectively.The present work may provide new insights into the design of nanoreactors to promote Li_(2)S_(1/2) growth in a three-dimensional process and accelerate conversion from solid Li_(2)S_(2) to solid Li_(2)S in high performance Li–S batteries.展开更多
基金supported by the Key-Area Research and Development Program of Guangdong Province(grant no.2020B0909-19005)the National Natural Science Foundation of China(grant nos.21975056 and 22179025)+1 种基金The Major and Special Project in the Field of Intelligent Manufacturing of the Universities in Guangdong Province(grant no.2020ZDZX2067)the Natural Science Foundation of Huizhou University(grant no.HZU202004).
文摘With advantages of low costs and high energy density,Li–S batteries are considered as one of the most promising energy storage devices.However,Li_(2)S_(2) with a high dissociation energy and insulative properties is hard to convert into Li_(2)S,resulting in underutilization of sulfur capacity.Herein,Co-Mo_(2)C@C yolk–shell spheres as nanoreactors were designed to confront this challenge rationally.The Co-Mo_(2)C@C-induced Li_(2)S_(1/2) nucleation and growth in the three-dimensional process and the cathode produced more Li_(2)S after full discharge.Experimental studies and theoretical calculations reveal that the conversion barrier from Li_(2)S_(2) into Li_(2)S was lowered while the diffusion of lithium ions and electron transfer accelerated when using the Co-Mo_(2)C@C catalyst.Based on the above advantages,the Co-Mo_(2)C@C/S cathode exhibits a high reversible capacity and excellent cyclic stability,such as an initial specific capacity of 1200 mAh g^(−1) at 0.1 C with 709 mAh g^(−1) at 1.0 C after 1000 cycles with a low capacity fading rate of 0.04%per cycle.Even at high densities of 3.0 C and 5.0 C,the specific capacities are 647.6 and 557.7 mAh g^(−1) after 400 cycles,respectively.Impressively,it also shows ca.770 and 900 mAh g^(−1) at 0.2 C after 50 cycles with high sulfur loadings of 4.2 and 5.1 mg cm−2,respectively.The present work may provide new insights into the design of nanoreactors to promote Li_(2)S_(1/2) growth in a three-dimensional process and accelerate conversion from solid Li_(2)S_(2) to solid Li_(2)S in high performance Li–S batteries.
