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To address the problem of the serious capacity fading in lithium–sulfur batteries, a multi‐functional PEO(polyethylene oxide)/LiFSI (lithium bis(fluorosulfonyl)imide)/PVDF (polyvinylidene fluoride) (PLP) gel polymer electrolyte is exploited by coating PLP on a carbon nanotubes (CNTs) based sulfur cathode (PLP‐S/CNTs) with a controlled thermal annealing process. The annealing process leads to the conformal infusion of PLP through the matrix of S/CNTs with retaining the amorphous phase of the PLP, which enhance the rate performance compared to the bare S/CNTs. The PLP coating drives the transformation of more elemental sulfur to Li2S2/Li2S without forming intermediary product by restraining soluble‐polysulfides formation. Furthermore, the PLP coating successfully inhibits the dissolution of Li2Sx (x > 4) in PEO and prevents the loss of active material in the cathode, which is confirmed by density functional theory calculations. Comprehensively, the PLP coating applied to the surface of the S/CNTs cathode exhibit significantly suppressed shuttle effect and greatly improve long‐term cycle stability of the lithium–sulfur battery. The synthesized PLP‐coated S/CNTs composite cathode demonstrates a high specific capacity of 573.6 mAh g−1 at a current density of 0.5 C after 1 000 cycles, even achieving 318.1 mAh g−1 at an extremely high C‐rate (6 C). which is unprecedented performance among the reported studies on coating technology. [ABSTRACT FROM AUTHOR]

Although efforts have been made to increase the Ni content in Ni-rich cathodes for Li-ion batteries with high specific capacities, an unstable surface of the cathode and electrolyte remains a significant challenge. To stabilize the surface, various protective layers – such as aluminum oxide (Al2O3) – have been introduced on the surface of Ni-rich cathodes. In this study, we used a facing-target sputtering (FTS) method to avoid the reaction of residual Li and moisture from the precursor for the coating method, and to build a dense, homogeneous, protective, ultrathin Al2O3 layer at the surface of NCM811. It was proven that FTS rules out the presence of the LiOH byproduct of residual Li on the NCM811 during surface modification. Ensuring interface protection by using FTS instead of atomic layer deposition with an H2O-based precursor was identified as a crucial determinant of the NCM811 performance. Our findings present an updated and promising process for stabilizing the surface, demonstrating the need to select a technique to achieve surface passivation of Ni-rich cathodes and improvements in cycling performance. [ABSTRACT FROM AUTHOR]