P-doped binary Ni/Fe-N-C for enhanced oxygen electrocatalysis performance.

Adjusting the micro-environment of highly dispersive metals on carbon supports has been proved to be effective for achieving enhanced electrocatalysis performance. Herein, we delicately design a phosphorus-doped binary NiFe-nitrogen-carbon material (denoted as P-NiFe-NC), taking advantage of the coupling reaction between phenylphosphonamide (P dopant) and formamide (the carbon and nitrogen sources). The XPS N 1s fine scan reveals the strong interplay of N and P by the positively shifted binding energy of pyridinic N species after P incorporation, and the chemical state of Fe species is influenced accordingly. In addition, the P doping can enlarge the specific surface area and increase the meso/macroporosity of NiFe-NC, thus contributing to the enhancement of mass transfer inside the pores. The P-NiFe-NC sample exhibits favorable bifunctional oxygen electrocatalysis performance, rendering an ORR half-wave potential of 0.85 V and an OER potential of 1.69 V@10.0 mA cm-2, superior to those of P-free NiFe-NC. Assembled into Zn-air batteries, P-NiFe-NC delivers a high specific power of 161.36 mW cm-2 and stable charge/discharge for over 100 h (corresponding to 300 cycles).

N4-Vacancy-Functionalized Carbon for High-Rate Li-Ion Storage.

Although heteroatom doping and pore management separately influence the Li+ adsorption and Li+ diffusion properties, respectively, merging their functions into a single unit is intriguing and has not been fully investigated. Herein, we have successfully incorporated both heteroatom doping and pore management within the same functional unit of N4-vacancy motifs, which is realized via acid etching of formamide-derived Zn-N4-functionalized carbon materials (Zn1NC). The N4-vacancy-rich porous carbon (V-NC) renders multiple merits: (1) a high N content of 13.94 atom % for large Li-storage capacity, (2) edged unsaturated N sites favoring highly efficient Li+ adsorption and desolvation, and (3) a shortening of the Li+ diffusion length through N4 vacancy, thereby enhancing the Li-storage kinetics and high-rate performance. This work serves as an inspiration for the creation of heteroatom-edged porous structures with controllable pore sizes for high-rate alkali-ion battery applications.