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Currently, there is an urgent demand for Ni-rich cathode materials with excellent electrochemical properties under harsh conditions; however, obtaining such materials is very challenging. Here, we propose an innovative modification strategy that combines gradient phosphate polyanion doping and dual-conductive layer (Li3PO4-PANI) coating. The phosphate polyanion gradient doping can be described as acting in a “support role” to optimize the crystal structure. Moreover, the dual-conductive (Li3PO4-PANI) layers can be described as acting in a “palisade role” to inhibit side reactions and enhance the ionic/electronic conductivity of the NCM cathode. For the NCM cathode, this strategy synergistically achieves three main objectives: enhancement of structure stability, improvement of the ionic/electronic conductivity of the interface, and reduction of residual lithium salts. The modified NCM cathode delivers superior cycling stability, with 81.4% capacity retention after 100 cycles (4.5 V/55 °C), whereas the original NCM shows only a quite low capacity retention (57.7%). Moreover, this strategy also significantly improves the rate performance of the NCM cathode. These results indicate that this innovative modification strategy can be utilized to enhance the electrochemical performance of the NCM cathode at 4.5 V and 55 °C.

Chemical looping partial oxidation of CH4 is a promising method for producing syngas with a suitable H2/CO ratio and avoiding the risk of explosion and use of an expensive air separation plant. However, regeneration of reduced oxygen carriers (OCs) by O2 usually leads to the enrichment of surface electrophilic O2– or O– species and thus CO2 formation and a decrease in total CO selectivity. In this work, it was found that the CO selectivity of the BaFe3Al9O19 hexaaluminate (BF3A) OC was greatly improved from 58% to 83% by tuning the regeneration period, with a CH4 conversion of 86%, an H2/CO ratio of 2, and a syngas yield of 4.2 mmol/g without significant carbon deposition. This resulted from the decrease in regeneration time (from 15 to 4.2 min), leading to a decrease in Fe3+ in Al(1), Al(2), and Al(3) sites (Fe1, Fe2, and Fe3) active for combustion of CH4 and an increase in reduced Fe2+ to Fe0 responsible for the partial oxidation of CH4. Consequently, the amount of CO2 decreased while that of CO increased significantly. In addition, unoxidized surface Fe0 resulting from shorter regeneration periods (5 and 4.2 min) acted as catalysts for dry reforming of CH4 and CO2 at the beginning of the reaction, which also contributed to the increase in CO formation for these two samples.