Combined high catalytic activity and polysulfide confinement in hierarchical carbon-encapsulated CoSe hollow core-shell spheres for high-performance lithium-sulfur batteries
Combined high catalytic activity and polysulfide confinement in hierarchical carbon-encapsulated CoSe hollow core-shell spheres for high-performance lithium-sulfur batteries
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用于高性能锂硫电池的分级碳封装 CoSe 空心核壳球中的高催化活性和多硫化物限制相结合
DOI：
10.1016/j.jpowsour.2021.230177
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发表时间：
2021
影响因子：
9.2
通讯作者：
Yang Liwen
中科院分区：
文献类型：
--
作者：
Li Lun;Xu Guobao;Liu Xiong;Huang Shouji;Wei Xiaolin;Yang Liwen
设计并构建了多级碳包覆CoSe（C-CoSe）空心核壳球，以缓解LiPS的穿梭效应，从而提高LSB的性能。所制备的C-CoSe微球由球形纳米聚集体作为空心核和N掺杂的碳壳组成。动力学实验和理论计算以及原位拉曼光谱表明，C-CoSe空心核壳微球通过化学吸附和物理约束作用有效包覆了LiPSs中间体，同时由于其在电化学反应中的强催化作用和优越的上级电子传导性，加速了LiPSs的转化动力学，从而有效抑制了穿梭效应。此外，作为硫主体，与分级多孔结构相关的足够的硫储存空间使得能够有效地适应体积变化，并且在硫负载为73%的情况下具有充分的功效。得益于上述优点，C-CoSe硫阴极表现出令人印象深刻的倍率性能和优异的循环稳定性。即使在3 mg cm-2的硫负载下，在0.5 C下也实现了584 mAh g-1的容量，并且在200次循环后容量保持在450 mAh g-1。我们的研究结果提供了一个有效的策略，设计先进的硫主机的性能增强的LSB。
Hierarchical carbon-encapsulated CoSe (designated as C–CoSe) hollow core-shell sphere is designed and constructed to relieve shuttle effect of the LiPSs, thereby leading to the performance enhancement of the LSBs. The prepared C–CoSe spheres comprise of spherical nano-aggregates as hollow core andN-doped carbon shell. Kinetics experiments and theoretical calculation as well as in situ Raman spectra reveal that the C–CoSe hollow core-shell spheres can effectively immobilize the LiPSs intermediates by chemical adsorption and physical confinement, and meanwhile accelerate conversion kinetics of the LiPSs owing to strong catalytic effect and superior electron conductivity during electrochemical reaction, thereby the shuttle effect being effectively inhibited. In addition, as a sulfur host, sufficient sulfur storage space related to hierarchical porous structure enable effective accommodation of volume change and full efficacy with sulfur loading of 73%. Benefiting from above advantages, the C–CoSe sulfur cathode exhibits impressive rate performance and excellent cycle stability. Even at a sulfur loading of 3 mg cm−2, a capacity of 584 mAh g−1at 0.5 C is achieved and the capacity is maintained 450 mAh g−1after 200 cycles. Our results provide an effective strategy to design advanced sulfur hosts for the performance enhancement of the LSBs.