Application of Li-oxygen(Li-O_(2)) battery is in urgent need of bifunctional ORR/OER electrocatalyst. A surface-functionalization CoP/Ti_(3)C_(2)Txcomposite was fabricated theoretically, with the optimized electronic ...Application of Li-oxygen(Li-O_(2)) battery is in urgent need of bifunctional ORR/OER electrocatalyst. A surface-functionalization CoP/Ti_(3)C_(2)Txcomposite was fabricated theoretically, with the optimized electronic structure and more active electron, which is beneficial to the electrochemical reaction. The accordion shaped Ti_(3)C_(2)Txis featured with large specific surface area and outstanding electronic conductivity, which is beneficial for the adequate exposure of active sites and the deposition of Li2O2. Transition metal phosphides provide more electrocatalytic active sites and present good electrocatalytic effect. The CoP/Ti_(3)C_(2)Txcomposite served as the electrocatalyst of Li-O_(2)battery reaches a high specific discharge capacity of 17,413 m Ah/g at 100 m A/g and the lower overpotential of 1.25 V, superior to those of the CoP and Ti_(3)C_(2)Txindividually. The composite of transition metal phosphides and MXene are applied in Li-O_(2)battery, not only demonstrating higher cycling stability of the prepared CoP/Ti_(3)C_(2)Txcomposite, but pointing out the direction for their electrochemical performance improvement.展开更多
Constructing interfaces in heterostructures is effective for modulating the electronic properties of electrocatalysts.The hollow CoMoO_(4)-Co_(3)O_(4) heterostructure(HCMCH)was prepared as a bifunctional electrocataly...Constructing interfaces in heterostructures is effective for modulating the electronic properties of electrocatalysts.The hollow CoMoO_(4)-Co_(3)O_(4) heterostructure(HCMCH)was prepared as a bifunctional electrocatalyst for Li-O_(2) battery.The different components in CoMoO_(4)-Co_(3)O_(4) heterostructure presented the efficient coupling and enhanced the electrocatalytic activity for aprotic oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),in which it improved the obviously reduced overpotential of 300 mV(compared with the pure Ketjen black(KB)electrode),enhanced reversibility of 80%capacity retention after 6 full cycles and the superior cyclability of more than 200 cycles with an optimized strategy.The battery performance of the HCMCH was not only associated with the unique hollow structure and rich active sites but also with coupling interface constructions synergetic effects attaching to the improving conductivity and optimized the discharge conversion.These results suggested that this HCMCH electrocatalyst was a promising candidate for the Li-O_(2) battery and it gave a novel insight for high performance electrocatalyst designing.展开更多
Design and fabrication of framework-structured porous precursors have been regarded as a prospective albeit challenging strategy to obtain bimetal/NC-enriched bifunctional elecrocatalysts. In this work, an effective b...Design and fabrication of framework-structured porous precursors have been regarded as a prospective albeit challenging strategy to obtain bimetal/NC-enriched bifunctional elecrocatalysts. In this work, an effective bottom-up approach involving solution-based self-assembly and a post-annealing process was developed to confine (Co, Zn)-N-C active sites into N-enriched graphitic carbon nanocages. This novel architecture containing N-doped-C stabilized bimetallic nanoparticles derived from ZIF precursors was well-studied by a series of characterization and analysis techniques. Details were given that these well-dispersed (Co, Zn) nanoparticles were encapsulated into the pyridinic-N-dominated graphitic carbon nanocage with a total metal loading of approximately 7.4 at.%. This favorable hierarchical structure not only enhances the electron conductivity, but also owns a sufficient BET surface area facilitating the gas-liquid-solid triphase reaction and producing more space to store discharge products. Importantly, results infer that the interesting nanoframes manifests a satisfying ORR/OER activity and enhanced cell performance whether liquid or solid-state electrolytes are used. As such, our work rationalizes that this type of cage-shaped bimetal-N-C material is promising for high-performance Li-O2 batteries.展开更多
基金supported by the National Science Foundations of China (Nos. 21871028, 21771024)China Postdoctoral Science Foundation (No. 2020M680430)。
文摘Application of Li-oxygen(Li-O_(2)) battery is in urgent need of bifunctional ORR/OER electrocatalyst. A surface-functionalization CoP/Ti_(3)C_(2)Txcomposite was fabricated theoretically, with the optimized electronic structure and more active electron, which is beneficial to the electrochemical reaction. The accordion shaped Ti_(3)C_(2)Txis featured with large specific surface area and outstanding electronic conductivity, which is beneficial for the adequate exposure of active sites and the deposition of Li2O2. Transition metal phosphides provide more electrocatalytic active sites and present good electrocatalytic effect. The CoP/Ti_(3)C_(2)Txcomposite served as the electrocatalyst of Li-O_(2)battery reaches a high specific discharge capacity of 17,413 m Ah/g at 100 m A/g and the lower overpotential of 1.25 V, superior to those of the CoP and Ti_(3)C_(2)Txindividually. The composite of transition metal phosphides and MXene are applied in Li-O_(2)battery, not only demonstrating higher cycling stability of the prepared CoP/Ti_(3)C_(2)Txcomposite, but pointing out the direction for their electrochemical performance improvement.
基金supported by the National Natural Science Foundation of China(Nos.22271018,12304037)Talent introduction and scientific research funds of Beijing Normal University(No.310432107)Interdisciplinary Research Foundation for Doctoral Candidates of Beijing Normal University(No.BNUXKJC2216).
文摘Constructing interfaces in heterostructures is effective for modulating the electronic properties of electrocatalysts.The hollow CoMoO_(4)-Co_(3)O_(4) heterostructure(HCMCH)was prepared as a bifunctional electrocatalyst for Li-O_(2) battery.The different components in CoMoO_(4)-Co_(3)O_(4) heterostructure presented the efficient coupling and enhanced the electrocatalytic activity for aprotic oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),in which it improved the obviously reduced overpotential of 300 mV(compared with the pure Ketjen black(KB)electrode),enhanced reversibility of 80%capacity retention after 6 full cycles and the superior cyclability of more than 200 cycles with an optimized strategy.The battery performance of the HCMCH was not only associated with the unique hollow structure and rich active sites but also with coupling interface constructions synergetic effects attaching to the improving conductivity and optimized the discharge conversion.These results suggested that this HCMCH electrocatalyst was a promising candidate for the Li-O_(2) battery and it gave a novel insight for high performance electrocatalyst designing.
基金National Basic Research Program of China (No. 2014CB932301)National Natural Science Foundation of China (No. 21473040)Science & Technology Commission of Shanghai Municipality, China (No. 08DZ2270500).
文摘Design and fabrication of framework-structured porous precursors have been regarded as a prospective albeit challenging strategy to obtain bimetal/NC-enriched bifunctional elecrocatalysts. In this work, an effective bottom-up approach involving solution-based self-assembly and a post-annealing process was developed to confine (Co, Zn)-N-C active sites into N-enriched graphitic carbon nanocages. This novel architecture containing N-doped-C stabilized bimetallic nanoparticles derived from ZIF precursors was well-studied by a series of characterization and analysis techniques. Details were given that these well-dispersed (Co, Zn) nanoparticles were encapsulated into the pyridinic-N-dominated graphitic carbon nanocage with a total metal loading of approximately 7.4 at.%. This favorable hierarchical structure not only enhances the electron conductivity, but also owns a sufficient BET surface area facilitating the gas-liquid-solid triphase reaction and producing more space to store discharge products. Importantly, results infer that the interesting nanoframes manifests a satisfying ORR/OER activity and enhanced cell performance whether liquid or solid-state electrolytes are used. As such, our work rationalizes that this type of cage-shaped bimetal-N-C material is promising for high-performance Li-O2 batteries.
