Boosting the Ni content in LiMO₂ (M = Ni, Co, Mn, etc.) layered oxides is a promising way to establish high-energy-density, low-cost cathodes, but the poor cathode surface stability is a daunting challenge for their practical viability. Herein, by constructing a dual-functional binder framework with a conductive polymer–polyaniline (PANI), the ultrahigh-Ni layered oxide cathode (LiNi_0.94Co_0.06O₂) exhibits significantly improved cyclability, with a capacity retention greatly increased from 47% to 81% over 1000 cycles in full cells. It is demonstrated that the acidic species (e.g., HF) in the electrolyte can be efficiently scavenged through a protonation process of PANI, hence the cathode surface reactivity is greatly suppressed, and the rock-salt phase propagation into bulk structure is considerably alleviated. Furthermore, the PANI binder system effectively prevents both the cathode-electrolyte interphase (CEI) and the anode-electrolyte interphase (AEI) from degrading to a thick “triple-layer” architecture upon extensive cycling, resulting in more robust, thinner CEI and AEI with regulated interphasial chemistry. Moreover, the delocalized π-conjugated electrons along the backbone of PANI facilitate fast electron transfer and promote rate capability even at low temperatures (−20 °C). This work sheds light on rational binder engineering for developing high-energy-density lithium-ion batteries with acceptable cycle life.

中文翻译：

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面向锂离子电池的长寿命超高镍层状氧化物阴极：使用双功能聚合物优化相间化学

提高LiMO ₂（M = Ni，Co，Mn等）层状氧化物中的Ni含量是建立高能量密度，低成本阴极的一种有前途的方法，但是不良的阴极表面稳定性对其挑战却是艰巨的挑战。实际可行性。在此，通过用导电聚合物-聚苯胺（PANI）构建双功能粘合剂骨架，超高Ni层状氧化物阴极（LiNi _0.94 Co _0.06 O ₂）表现出显着改善的循环性，容量保持率从47％大大提高到了在完整的电池中，经过1000次循环后达到81％。已经证明，酸性物质（例如。通过PANI的质子化过程可以有效地清除电解质中的HF），因此极大地抑制了阴极表面反应性，并且极大地减轻了岩盐相向本体结构的传播。此外，PANI粘合剂系统有效地防止了阴极-电解质间相（CEI）和阳极-电解质间相（AEI）在广泛的循环过程中降解为厚的“三层”结构，从而使CEI和AEI更坚固，更薄具有受调控的相间化学作用。此外，即使在低温（-20°C）下，沿PANI主链的离域π共轭电子也有助于快速电子转移并提高速率能力。这项工作为开发具有可接受的循环寿命的高能量密度锂离子电池的合理粘合剂工程提供了启示。