The reduction process of ilmenite by hydrogen and methane under MPCVD was analyzed by XRD result. The reduction degree of ilmenite increased with adding methane, the case similar to reduction rate. The mechanism of re...The reduction process of ilmenite by hydrogen and methane under MPCVD was analyzed by XRD result. The reduction degree of ilmenite increased with adding methane, the case similar to reduction rate. The mechanism of reduction process changed with the increasement of methane flow because of the formation of carbon nanotubes （CNTs）. The morphology of reduced samples was observed by SEM, and it was found that CNTs played an important role in the fracture of ilmenite particles. The reduction kinetics showed that the reduction was rate-controlling for hydrogen, and diffusion-controlling when hydrogen mixed with high flow methane.展开更多
In this paper,we use microwave reduction strategy to synthesize a new bi-functional sulfur host material at the service of cathode substrate for lithium-sulfur batteries(LSBs),the composite is made of hierarchical por...In this paper,we use microwave reduction strategy to synthesize a new bi-functional sulfur host material at the service of cathode substrate for lithium-sulfur batteries(LSBs),the composite is made of hierarchical porous carbon foam supported carbon-encapsulated chromium carbide nano-particles(Cr_(3)C_(2)@C/HPCF),in which the well-distributed conductive Cr_(3)C_(2) nano-particles can act as powerful chemical adsorbent and are effective in restraining the shuttle effect of lithium polysulfides(LiPSs).Test results show that the Cr_(3)C_(2)@C/HPCF based sulfur electrodes with 75 wt.%of sulfur exhibit a high initial discharging capacity of 1,321.1 mAh·g^(−1) at 0.1 C(3.5 mg·cm^(−2)),and a reversible capacity can still maintain stability at 1,002.1 mAh·g^(−1) after 150 cycles.Even increasing the areal sulfur loading to 4 mg·cm^(−2),the electrodes can still deliver an initial discharging capacity of 948.0 mAh·g^(−1) at 0.5 C with ultra-slow capacity decay rate of 0.075%per cycle during 500 cycles.Furthermore,the adsorption energy between the Cr_(3)C_(2) surface and LiPSs as well as theoretic analysis based on first-principles is also investigated.展开更多
基金National Natural Science Foundation of China(No.51072140)the Program for Excellent Youth Team and the Scientific Research Foundation of the Higher Education Commission of Hubei Province of China(Nos.Z200715001 and T201004)the Program for Excellent Subject Leader of Wuhan(No.201150530151)
文摘The reduction process of ilmenite by hydrogen and methane under MPCVD was analyzed by XRD result. The reduction degree of ilmenite increased with adding methane, the case similar to reduction rate. The mechanism of reduction process changed with the increasement of methane flow because of the formation of carbon nanotubes （CNTs）. The morphology of reduced samples was observed by SEM, and it was found that CNTs played an important role in the fracture of ilmenite particles. The reduction kinetics showed that the reduction was rate-controlling for hydrogen, and diffusion-controlling when hydrogen mixed with high flow methane.
基金The authors appreciate support by the Natural Science Foundation of Anhui Province(No.1908085ME147)Projects of International Cooperation and Exchanges in Anhui Provincial Key Project of Research(No.202004b11020010)+2 种基金Shenzhen Basic Research Program(Nos.JCYJ20190808141611189,JCYJ20170818100134570,and JCYJ20160422091418366)Basic and applied basic research fund of Guangdong Province(No.2020A1515011018)we are grateful to Instrumental Analysis Center of Shenzhen University(Xili Campus)for the help with TEM,and thanks for technical support by Ceshigo Research Service Agency(www.ceshigo.com)for XAS,ACSTEM and DFT/MD.
文摘In this paper,we use microwave reduction strategy to synthesize a new bi-functional sulfur host material at the service of cathode substrate for lithium-sulfur batteries(LSBs),the composite is made of hierarchical porous carbon foam supported carbon-encapsulated chromium carbide nano-particles(Cr_(3)C_(2)@C/HPCF),in which the well-distributed conductive Cr_(3)C_(2) nano-particles can act as powerful chemical adsorbent and are effective in restraining the shuttle effect of lithium polysulfides(LiPSs).Test results show that the Cr_(3)C_(2)@C/HPCF based sulfur electrodes with 75 wt.%of sulfur exhibit a high initial discharging capacity of 1,321.1 mAh·g^(−1) at 0.1 C(3.5 mg·cm^(−2)),and a reversible capacity can still maintain stability at 1,002.1 mAh·g^(−1) after 150 cycles.Even increasing the areal sulfur loading to 4 mg·cm^(−2),the electrodes can still deliver an initial discharging capacity of 948.0 mAh·g^(−1) at 0.5 C with ultra-slow capacity decay rate of 0.075%per cycle during 500 cycles.Furthermore,the adsorption energy between the Cr_(3)C_(2) surface and LiPSs as well as theoretic analysis based on first-principles is also investigated.
基金supported by Australian Research Council (FL180100029, DP220103498, and DE190100445)the financial support from the South China University of Technologythe financial support from the Chinese Academy of Sciences (CAS) and Ganjiang Innovation Academy, CAS
