Nickel-rich layered oxides are promising candidates for next-generation lithium-ion batteries. However, nickel-rich cathodes largely suffer from poor cyclability due to interfacial instability and intergranular cracking, particularly under high voltages and elevated temperatures. Herein, a multifunctional binder (PAA–PN) derived from the cross-linking of sodium phytate (PN) and poly(acrylic acid) (PAA) was designed to stabilize the LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) working under a cutoff voltage of 4.6 V. The PAA–PN promotes the formation of dual protective layers, consisting of an outer stable cathode electrolyte interface and an inner thin rock-salt phase on the NCM811 surface, effectively mitigating electrolyte decomposition, transition-metal dissolution, and phase-fatigue issues. Additionally, the robust elastic PAA–PN cross-linking network and chelation of PAA–PN with the NCM811 surface effectively inhibit intergranular cracking. Benefiting from these multifunctional advantages, NCM811 cathodes with PAA–PN binder achieve capacity retention of 95.1% (25 °C) and 84.7% (45 °C) after 100 cycles at 4.6 V, respectively.

中文翻译：

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植酸钠交联聚丙烯酸作为多功能水性粘合剂可将 LiNi0.8Co0.1Mn0.1O2 稳定至 4.6 V


富镍层状氧化物是下一代锂离子电池的有前途的候选者。然而，由于界面不稳定性和晶间开裂，富镍阴极在很大程度上存在循环性差的问题，尤其是在高电压和高温下。本文设计了一种由植酸钠 （PN） 和聚丙烯酸 （PAA） 交联衍生的多功能粘合剂 （PAA-PN），以稳定在 4.6 V 截止电压下工作的 LiNi_0.8Co_0.1Mn_0.1O₂ （NCM811）。PAA-PN 促进双重保护层的形成，由外部稳定的阴极电解质界面和 NCM811 表面的内部薄岩盐相组成，有效缓解电解质分解、过渡金属溶解和相疲劳问题。此外，强大的弹性 PAA-PN 交联网络和 PAA-PN 与 NCM811 表面的螯合可有效抑制晶间开裂。得益于这些多功能优势，采用 PAA-PN 粘合剂的 NCM811 阴极在 4.6 V 下循环 100 次后，容量保持率分别为 95.1% （25 °C） 和 84.7% （45 °C）。