Here, we report the improved energy storage performance of lithium-ion batteries consisting of a hexagonal-layered LiNi_0.8Co_0.15Al_0.05O₂ (LNCA) cathode and a spinel-type Li₄Ti₅O₁₂-Rutile-TiO₂ (LTO-R-TiO₂) dual-phase anode upon nanocoating of Al₂O₃ and electronically conducting poly(3,4-ethylenedioxythiophene) (PEDOT). LNCA and LTO-R-TiO₂ were prepared by rapid microwave-assisted hydrothermal (MW-HT) and solid-state (MW-SS) techniques within 10–30 min compared to conventional techniques that require >35 h. The crystal structure, lattice parameters, and microstrain (ε) of the electrode materials induced by microwave irradiation (MW-HT and MW-SS) were determined using the Williamson–Hall equation deduced from X-ray diffraction. The Raman and Fourier transform infrared spectroscopy studies delineated the existence of PEDOT and dual phases of LTO-R-TiO₂. Field emission-scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy analyses revealed homogeneous distribution of transition-metal ions along with the polymer and Al₂O₃ over the electrode surface. The UV–visible and DRS spectroscopies unveiled the reduction in band-gap energies (E_g) of LTO-R-TiO₂ after PEDOT coating. Indeed, the LNCA-Al₂O₃/PEDOT hybrid cathode exhibited an enhanced discharge capacity of 209 mAh g^–1 with a Coulombic efficiency of 98% compared to the uncoated pristine cathode with a discharge capacity of 194 mAh g^–1 with a Coulombic efficiency of 91%. On the other hand, the optimized LTO-R-TiO₂/PEDOT hybrid anodes exhibited a reversible capacity of 174 mAh g^–1 at 0.2 C compared to the pristine anode with a reversible capacity of 169 mAh g^–1 at 0.2 C vs Li/Li⁺ in the half-cell configuration. Besides, the LNCA-Al₂O₃/PEDOT||LTO-R-TiO₂/PEDOT full cells delivered an energy density of 156.2 Wh kg^–1 with excellent cyclability over 200 cycles at 1 C with a capacity retention of 90%. The FE-SEM image illustrated the absence of structural/mechanical damage in LNCA-Al₂O₃/PEDOT and LTO-R-TiO₂/PEDOT electrodes after 200 cycles in the full-cell configuration. Hence, amorphous phases of the PEDOT matrix and Al₂O₃-coating layers tend to promote the electrical conductivity and reaction kinetics of both electrodes. Therefore, this work provides an energy-efficient and cost-effective synthesis approach driven by microwave irradiation for the development of high-energy-density lithium-ion batteries.

中文翻译：

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通过微波辅助反应的高能量密度 LiNi0.8Co0.15Al0.05O2 和双相 LTO-R-TiO2 材料：通过 Al2O3 和 PEDOT 的纳米涂层缓解容量衰减机制

在这里，我们报告了由六边形层状 LiNi _0.8 Co _0.15 Al _0.05 O ₂ (LNCA) 阴极和尖晶石型 Li ₄ Ti ₅ O ₁₂ - Rutile -TiO ₂ (LTO - R -TiO ₂ ) 基于Al ₂ O ₃纳米涂层和导电聚(3,4-亚乙基二氧噻吩) (PEDOT)的双相阳极。LNCA和LTO- ř -TiO ₂与需要 >35 小时的传统技术相比，通过快速微波辅助水热 (MW-HT) 和固态 (MW-SS) 技术在 10-30 分钟内制备。使用从 X 射线衍射推导出的 Williamson-Hall 方程确定由微波辐射（MW-HT 和 MW-SS）引起的电极材料的晶体结构、晶格参数和微应变（ε）。拉曼和傅立叶变换红外光谱研究描绘了 PEDOT 和 LTO- R- TiO ₂双相的存在。场发射扫描电子显微镜 (FE-SEM) 和 X 射线光电子能谱分析揭示了过渡金属离子与聚合物和 Al ₂ O _{3 的}均匀分布在电极表面。紫外-可见光和 DRS 光谱揭示了PEDOT 涂层后LTO- R- TiO ₂带隙能量 ( E _g )的降低。实际上，LNCA-Al系₂ ö ₃ / PEDOT阴极混合表现出209毫安克增强的放电容量^-1与98％的库仑效率与用194毫安g的放电容量未涂覆原始阴极^-1与库仑效率为 91%。另一方面，优化的 LTO- R- TiO ₂ /PEDOT 混合负极的可逆容量为 174 mAh g ^–1在 0.2 C 下与原始阳极相比，在 0.2 C vs Li/Li ⁺半电池配置中具有 169 mAh g ^–1的可逆容量。此外，LNCA-Al ₂ O ₃ /PEDOT|| LTO- R -TiO ₂ /PEDOT 全电池的能量密度为 156.2 Wh kg ^–1，在 1 C 下循环超过 200 次具有出色的循环性能，容量保持率为 90%。FE-SEM 图像说明 LNCA-Al ₂ O ₃ /PEDOT 和LTO- R -TiO _{2 中}没有结构/机械损伤/PEDOT 电极在全电池配置中经过 200 次循环后。因此，PEDOT 基体和Al ₂ O ₃涂层的非晶相倾向于促进两个电极的导电性和反应动力学。因此，这项工作为开发高能量密度锂离子电池提供了一种由微波辐射驱动的节能且具有成本效益的合成方法。