Designing ultrathick and hierarchical electrodes is effective to deal with the challenge of high areal capacity and high power density for lithium-ion batteries (LIBs) manufacturing. Here, a thick electrode with hierarchical porous and multidimensional conductive network is fabricated by 3D printing technology, in which both the conducting polymer of poly(3,4-ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS) and graphene oxide (GO) play the dual roles as binders and conductive agents. As a consequence, the 3D-printed thick electrode (~900 μm) with a mass loading of ~47 mg/cm² exhibits a good rate capability of 122 mA·h/g at 2 C, a high areal capacity of up to 5.8 mA·h/cm², and stable cycling performance of ~95% capacity retention after 100 cycles. Moreover, the C-O-S bond is further confirmed by the spectral analysis and the DFT calculation, which not only hinders the stack of nanosheets but enhances the mechanical stability and electronic conductivity of electrodes. A stable covalent multidimensional conductive network constructed by 3D-printing technology provides a new design strategy to improve the performance of LIBs.

The development of high energy density LiNi_0.5Mn_1.5O₄ (LNMO) cathode materials for lithium-ion batteries are challenged by capacity degradation, which becomes more aggravated particularly at elevated temperatures. Thus, the practical strategy with facile craft and the viability of large-scale preparation for industrialized applications should be developed urgently. In this work, a micron-sized LNMO single crystals is synthesized by a facile two-step method consisting of an alcohol gel solvent method and a segmented sintering reaction. Results show that the truncated polyhedron LNMO-900 sample, with the moderate D₅₀ characteristic value of 4.429 μm and the highest tap density of 2.31 g cm⁻³, provides a stable structural and chemical stability even at elevated testing temperature due to its moderate specific surface area and the few Fd-3m phase. The LNMO/Li half-cells display more excellent capacity retention (87.3% at 1C and 25 °C after 500 cycles) and better thermal stability (76.65% at 1C and 55 °C after 200 cycles) than those of the single crystals of LNMO-850 and LNMO-950. Besides, the XPS, in-situ EIS and electrochemical tests results also prove that the LNMO-900 exhibits the lowest electrolyte decomposition degree, owing to a thin and effective solid-electrolyte interfacial film formed after cycles.