Ni-rich layered oxides hold significant promise as cathodes for lithium-ion batteries. Nevertheless, the susceptibility of their interphase at deep state-of-charge (SoC) imposes substantial limitations on their practical viability. Herein, we propose a water-based composite binder of dextran sulfate sodium-co-poly(acrylic acid) lithium (DSS-co-PAA(Li)) to address this dilemma. Capitalizing on the robust coordination bond interaction between the sulfate acid groups of DSS chains and transition-metal (TM) ion on the surface lattice, this functionally designed binder not only augments the cohesiveness within the electrode architecture but also effectively suppresses the vigorous reaction involving the highly labile Ni⁴⁺ and lattice O at the interphase. This attenuation is achieved by mitigating the undesirable phase transition and widening the energy gap between the Ni 3d and O 2p band of NCM₈₁₁. Consequently, the NCM₈₁₁ cathode with DSS-co-PAA(Li) binder yields an enhanced initial Coulombic efficiency (ICE) of 93.3% and capacity retention of nearly 90% after 200 cycles.

中文翻译：

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多功能水基粘合剂固结富镍层状正极的脆弱界面相

富镍层状氧化物作为锂离子电池的阴极具有巨大的前景。然而，它们在深充电状态 (SoC) 下相间的敏感性对其实际可行性造成了很大的限制。在此，我们提出了一种水性葡聚糖硫酸钠-共聚丙烯酸锂（DSS- co -PAA(Li)）复合粘合剂来解决这一困境。利用DSS链的硫酸基团与表面晶格上的过渡金属（TM）离​​子之间强大的配位键相互作用，这种功能设计的粘合剂不仅增强了电极结构内的内聚性，而且还有效地抑制了涉及电极结构的剧烈反应。界面处高度不稳定的 Ni ^{4+和晶格 O。这种衰减是通过减轻不期望的相变并加宽NCM} ₈₁₁的Ni 3d 和O 2p 带之间的能隙来实现的。因此，采用 DSS- co -PAA(Li) 粘合剂的NCM ₈₁₁正极的初始库仑效率 (ICE) 提高到 93.3%，200 次循环后容量保持率接近 90%。