Enhancing the stability of Li2NiO2 cathode additive with polyborosiloxane coating for high-energy lithium-ion batteries.

[Display omitted] • Polyborosiloxane (PBS) layer enhances moisture resistance and ionic conductivity of Li 2 NiO 2. • The PBS layer significantly diminishes the interfacial resistance and improves the cycling performance of Li 2 NiO 2. • The full-cell containing PBS@LNO outperformed, preserving 71.8 % capacity after 300 cycles. Li 2 NiO 2 has garnered considerable interest as a Li-excess cathode additive for high-energy lithium-ion batteries (LIBs), attributed to its high irreversible capacity during the initial cycle and an operating voltage comparable with that of commercial cathode materials. However, its integration into practical applications is limited by its suboptimal cycling performance owing to moisture instability and gas evolution. To surmount these obstacles, we developed a hybrid surface coating strategy employing polyborosiloxane (PBS)—a structural derivative of polydimethylsiloxane (PDMS) synthesized with boric acid (H 3 BO 3)—applied to a Li 2 NiO 2 cathode additive. The bi-functional of the PBS layer enhances moisture resistance and ionic conductivity on the Li 2 NiO 2 surface. A hydrophobic, elastic PDMS matrix offers conformal coverage, forestalling adverse moisture-induced side reactions. The introduction of H 3 BO 3 into the PDMS matrix on the Li 2 NiO 2 surface fosters the formation of Li–B–O bonds, thus augmenting the ionic conductivity of the coating. This innovative approach with the PBS layer significantly diminishes the interfacial resistance and improves the cycling performance of Li 2 NiO 2 while preventing substantial structural degradation. In a full-cell configuration incorporating a PBS-coated Li 2 NiO 2 cathode additive with a LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode and a SiO x /Graphite anode, the enhanced energy density and sustained stable cycling performance exceed 300 cycles. This hybrid layer can aid in producing longer-lasting, more efficient LIBs that can fulfill the requirements for use in high-energy storage solutions. [ABSTRACT FROM AUTHOR]