Mussel-inspired polydopamine-assisted uniform coating of Li+ conductive LiAlO2 on nickel-rich LiNi0.8Co0.1Mn0.1O2 for high-performance Li-ion batteries

Tuning Lithiophilic Sites of Ag-Embedded N-Doped Carbon Hollow Spheres via Intentional Blocking Strategy for Ultrastable Li Metal Anode in Rechargeable Batteries

“…PDA exhibits excellent adhesion to various surfaces. − According to previous studies, PDA can be easily coated on various surfaces under aqueous solution conditions and converted into NC through carbonization. ,, Because the dopamine monomer is self-polymerized in an aqueous solution with a pH of 8.5, the surface of SiO 2 @Ag is uniformly coated with PDA through strong interactions by the catechol groups. , To obtain Ag@NC@LAZP, a secondary surface modification was performed using the abundant hydroxyl groups of the PDA deposited on the SiO 2 @Ag@PDA surface. Because PDA provides binding sites for anchoring various metal ions in an aqueous solution, it may be induced to be uniformly positioned in the LAZP coating process on the surface of the SiO 2 @Ag@PDA. , Subsequently, an NC (converted from the PDA) and crystalline LAZP layers were obtained through the calcination process. The hollow sphere structure is formed by removing SiO 2 template through KOH etching treatment. , As a result, the particles of Ag@NC@LAZP are the hollow spheres with the shell consisting of double layers (NC inner layer and LAZP outer layer).…”

“…Several studies have proven that this strategy can effectively induce the Li metal to be preferentially plated inside the hollow structure. ,, However, the NC generated from the PDA that primarily constructs the hollow sphere structure is lithophilic; therefore, the deposition of Li outside the hollow spheres cannot be prevented because the NC is exposed outside the hollow spheres. , In addition, the Li metal deposited outside the hollow spheres is exposed to an electrolyte and continuously forms an unstable SEI layer, leading to the formation of dendritic growth of metallic Li and unwanted side reactions concerning electrolyte consumption. , Therefore, we designed a strategy to guide Li metal deposition into the hollow sphere rather than on the outer surface by uniformly coating the NC with a Li-ion-conductive but electron-insulating material. The material to be applied as an outer layer should meet the following requirements: (i) the Li-ion conductivity should be high so as not to interfere with the transport of Li ions inside and outside the hollow spheres; however, its electronic conductivity should be low. , (ii) It should be electrochemically stable and have excellent mechanical strength, thereby improving structural stability, mitigating volume expansion, and ensuring that the hollow sphere structure does not collapse. ,− (iii) It should exhibit sufficient adhesion with the inner layer to prevent Li from growing between the inner and outer layers. ,, Based on the above requirements, we selected LAZP, which is well known as a solid electrolyte, as the outer layer and expected to obtain better cycling stability for the Li metal anodes through the introduction of LAZP.…”

“…Because PDA provides binding sites for anchoring various metal ions in an aqueous solution, it may be induced to be uniformly positioned in the LAZP coating process on the surface of the SiO 2 @Ag@PDA. 38,39 Subsequently, an NC (converted from the PDA) and crystalline LAZP layers were obtained through the calcination process. The hollow sphere structure is formed by removing SiO 2 template through KOH etching treatment.…”

“…27,48−50 (iii) It should exhibit sufficient adhesion with the inner layer to prevent Li from growing between the inner and outer layers. 6,38,39 Based on the above requirements, we selected LAZP, which is well known as a solid electrolyte, as the outer layer and expected to obtain better cycling stability for the Li metal anodes through the introduction of LAZP. Nano-encapsulation of Li metal inside the hollow spheres can provide stable electrochemical cycling behavior because it reduces side reactions by avoiding the direct contact of Li metal with the liquid electrolyte.…”

Surface Engineering of Ni-Rich Cathodes Enables Homogeneous Doping of High-Valence Mo Ions for Li-Ion Batteries

“…First, dopamine undergoes self-polymerization and forms an even coating layer on the Ni 0.83 Co 0.11 Mn 0.06 (OH) 2 surface. Subsequently, molybdate was added to form a uniform Mo-PDA coating, facilitated by the strong complexation between the phenol hydroxyl group and the metal ion. − During the calculation process, the PDA completely decomposes and the Mo is dispersed uniformly into the lattice . SEM was applied for the morphology observation of the precursor before and after premodification (Figure S1).…”