Aqueous Zn-S batteries have shown great potential in advanced en-ergy storage systems due to their low cost,high theoretical capacity,and in-trinsic safety.However,the slow kinet-ics and low electrical conductivity of...Aqueous Zn-S batteries have shown great potential in advanced en-ergy storage systems due to their low cost,high theoretical capacity,and in-trinsic safety.However,the slow kinet-ics and low electrical conductivity of sul-fur prevent the full use of their capacity,leading to poor cycling performance.We used graphite carbon nitride(g-C_(3)N_(4))as the nitrogen source,and nitrogen-doped Ketjenblack(NKB)was synthesized by solid-phase calcination for use as the sulfur host.Results demonstrate that pyrrolic nitrogen serves as the primary catalytic active site in the sulfur reduction process.The high electronegativity of nitrogen significantly alters the charge distribution of the carbon matrix,changing the electron distribution around sulfur and rendering it electron-rich,which increases the interaction between S and Zn^(2+)and accelerates the reduction kinetics.NKB also forms a three-dimensional cross-linked carbon sphere network,providing abundant defect sites and a large specific surface area,which facilitates electron transfer and improves electrolyte wettability.Combined with the contribution of the ZnI2 additive,the Zn-S battery prepared with the precursor of a g-C_(3)N_(4)∶KB ratio of 3∶4 achieved an ultrahigh discharge capacity of 2069 mAh g^(-1) at a current density of 1 A/g.It also had an excellent rate performance(1257 mAh g^(-1) at 10 A/g)and a long cycling stability(705 mAh g^(-1) after 180 cycles at 5 A/g).This study provides a simple and effective strategy for improving the reduction kinetics of the sulfur cathode in Zn-S batteries and design-ing advanced cathode materials.展开更多
文摘目的探讨急性脑梗死(acute cerebral infarction,ACI)患者脑电图、血清胰岛素生长因子1(insulin-like growth factor 1,IGF-1)、神经元特异性烯醇化酶(neuron-specific enolase,NSE)与病灶体积及美国国立卫生研究院卒中量表(National Institute of Health stroke scale,NIHSS)评分的关系。方法选择2021年8月至2022年12月在南京市溧水区人民医院神经内科首次确诊的ACI患者218例,根据病灶体积分为大体积组63例、中体积组103例和小体积组52例。检测患者脑电图(δ+θ)与(α+β)功率比[(δ+θ)/(α+β)ratio,DTABR]、大脑对称指数(brainspine interface,BSI)、血清IGF-1和NSE水平,观察上述指标与MRI检查脑梗死病灶体积、NIHSS评分、阿替普酶溶栓后2周、4周时NIHSS评分的相关性。结果中体积组和大体积组IGF-1水平明显低于小体积组,NSE、DTABR、BSI明显高于小体积组(P<0.05);大体积组IGF-1水平明显低于中体积组,NSE、DTABR、BSI明显高于中体积组(P<0.05)。DTABR、BSI、血清NSE与病灶体积(r=0.563,P=0.000;r=0.318,P=0.038;r=0.673,P=0.000)和治疗前NIHSS评分(r=0.499,P=0.000;r=0.362,P=0.013;r=0.750,P=0.001)呈显著正相关。血清IGF-1水平与病灶体积(r=-0.572,P=0.000)和治疗前NIHSS评分(r=-0.438,P=0.001)呈显著负相关。DTABR、BSI、血清NSE、病灶体积均与溶栓后2、4周NIHSS评分呈正相关,IGF-1与溶栓后2、4周NIHSS评分呈负相关(P<0.05,P<0.01)。结论ACI患者脑电图、IGF-1和NSE与病灶体积和溶栓后NIHSS评分显著相关。
文摘Aqueous Zn-S batteries have shown great potential in advanced en-ergy storage systems due to their low cost,high theoretical capacity,and in-trinsic safety.However,the slow kinet-ics and low electrical conductivity of sul-fur prevent the full use of their capacity,leading to poor cycling performance.We used graphite carbon nitride(g-C_(3)N_(4))as the nitrogen source,and nitrogen-doped Ketjenblack(NKB)was synthesized by solid-phase calcination for use as the sulfur host.Results demonstrate that pyrrolic nitrogen serves as the primary catalytic active site in the sulfur reduction process.The high electronegativity of nitrogen significantly alters the charge distribution of the carbon matrix,changing the electron distribution around sulfur and rendering it electron-rich,which increases the interaction between S and Zn^(2+)and accelerates the reduction kinetics.NKB also forms a three-dimensional cross-linked carbon sphere network,providing abundant defect sites and a large specific surface area,which facilitates electron transfer and improves electrolyte wettability.Combined with the contribution of the ZnI2 additive,the Zn-S battery prepared with the precursor of a g-C_(3)N_(4)∶KB ratio of 3∶4 achieved an ultrahigh discharge capacity of 2069 mAh g^(-1) at a current density of 1 A/g.It also had an excellent rate performance(1257 mAh g^(-1) at 10 A/g)and a long cycling stability(705 mAh g^(-1) after 180 cycles at 5 A/g).This study provides a simple and effective strategy for improving the reduction kinetics of the sulfur cathode in Zn-S batteries and design-ing advanced cathode materials.
