用固态电解质取代液态电解液构建的固态锂电池具有良好的安全性能，且可以匹配锂金属负极和高压正极材料以满足对高能量密度的需求。但是，固态锂电池中由于固态电解质和电极间的固-固接触导致界面阻抗大，界面稳定性差和正极内部缺乏离子输运路径，致使其在高负载下的倍率性能和循环稳定性差。为解决以上问题，本论文制备了碳包覆的Li1.4Al0.4Ti1.6(PO4)3纳米线（C@LATP NW）并在正极中构建了高效稳定的锂离子传输网络，改善了正极内部的锂离子传输动力学，同时利用碳酸乙烯亚乙酯（VEC）和2-丙烯酸-2-甲氧基乙酯（MEA）聚合在电极/电解质界面原位构筑了界面层（PVM），降低了界面阻抗，提升了界面稳定性。首先，揭示了聚偏氟乙烯（PVDF）基固态电池中N,N-二甲基甲酰胺（DMF）和锂离子（Li+）的溶剂化结构（[Li(DMF)x]+）由PVDF基电解质向正极中有限的物理扩散行为和DMF在正极中的不稳定性。利用C@LATP NW在正极中构建了高效稳定的锂离子传输网络，通过C@LATP NW对DMF的强吸附作用使DMF紧紧包裹在C@LATP NW的表面，促进了[Li(DMF)x]+在正极中的扩散，结合C@LATP NW内部的LATP体相实现了锂离子的多路径传输，改善了正极中的锂离子输运效率，提升了正极活性材料的利用率。而且C@LATP NW表面的多孔碳层可以疏散集中攻击DMF的电子，在正极中给DMF提供了稳定的栖息空间，显著提升了正极结构稳定性。添加C@LATP NW的NCM811复合正极组装的PVDF基固态电池在15 mg cm-2的高负载下0.1C循环50次后，仍然还有85%的容量保持率，显著改善了PVDF基固态电池高负载下的电化学性能。其次，通过VEC和MEA聚合构筑了电极/固态电解质间的原位固态化界面层，改善界面接触，提升了界面锂离子传输动力学，同时使锂离子在负极侧的沉积和剥离更均匀，抑制锂枝晶的生长，其中氟代碳酸乙烯酯（FEC）添加剂促进富含LiF的稳定固态电解质膜（SEI）的形成，提升了界面稳定性。PVM界面层使极限电流密度高达3.60 mA cm-2，锂离子扩散系数从2.299×10-14 cm2 S-1提升到1.317×10-13 cm2 S-1，在30 mg cm-2的高负载下也表现出良好的循环稳定性。本论文通过对固态电池正极中的离子输运和界面进行调控，改善了固态电池在高负载下的电化学性能，为高能量密度固态锂电池的构筑提供了参考。

Solid state battery constructed with solid electrolyte instead of liquid electrolyte has good safety performance, and can be matched with lithium metal anode and high voltage cathode material to meet the demand of high energy density. However, solid-solid contact between solid-state electrolyte and electrode leads to the lack of lithium ion transport path in the cathode, and large interfacial impedance and poor interfacial stability will lead to poor rate performance and cycle stability of solid-state lithium batteries with high cathode loading. Therefore, in this work, an efficient and stable lithium ion transport network was constructed by carbon-coated Li1.4Al0.4Ti1.6(PO4)3 nanowires (C@LATP NW) in the cathode to improve the dynamic performance of lithium ion transport inside the cathode. In addition, the interface layer (PVM) was constructed in situ at the electrode/electrolyte interface by the polymerization of vinyl ethyl carbonate (VEC) and 2-methoxyethyl acrylate (MEA), which reduced the interface impedance and improved the interface stability.Firstly, the limited physical diffusion behavior of [Li(DMF)x]+ from the polyvinylidene fluoride (PVDF) electrolyte to the cathode and the instability of N,N-Dimethylformamide (DMF) in the cathode of PVDF based solid state batteries were revealed. An efficient and stable lithium ion transport network was constructed in the cathode by C@LATP NW. Through the strong adsorption of DMF on C@LATP NW, DMF was tightly wrapped on the surface of C@LATP NW, which promoted the diffusion of [Li(DMF)x]+ in the cathode. Combined with the LATP bulk phase in C@LATP NW, the multipath transmission of lithium ions is realized, which improve the transport efficiency of lithium ions and the utilization of active material in the cathode. Moreover, the porous carbon layer on the surface of C@LATP NW can evacuate the electrons concentrated on attacking DMF, providing a stable habitat space for DMF in the cathode, and significantly improving the stability of the cathode structure. The PVDF-based solid state lithium battery was assembled by C@LATP NW-NCM811 composite cathode with 15mg cm-2 loading. The capacity retention was 85% after 50 cycles at 0.1C, which significantly improved the electrochemical performance of PVDF-based solid state lithium battery with high loading.Secondly, the electrode/solid electrolyte in situ solid-state interface layer was constructed by VEC and MEA polymerization, which improved the interface contact and enhanced the dynamic performance of lithium ion transport. Moreover, the deposition/stripping of lithium ions on the anode is uniform, and the lithium dendrites are inhibited. The FEC additive promotes the formation of LiF-rich stable SEI and improves the interfacial stability. The PVM layer makes the critical current density up to 3.60 mA cm-2, the lithium ion diffusion coefficient is increased from 2.299×10-14 cm2 S-1 to 1.317×10-13 cm2 S-1, and it also showed good cyclic stability with high cathode loading of 30 mg cm-2.In this work, by regulating the ion transport in the cathode and interface of solid-state battery, the electrochemical performance of solid-state battery with high loading is improved, which provides a reference for the construction of solid-state lithium battery with high energy density.