RESOURCES

Abstract
A bottleneck limiting the practical application of lithium metal anodes is the uncontrolled growth of lithium dendrites caused by gradient distributed Li+ from separators to collectors. Herein{,} 3D-printed frameworks with a gradient distributed heterojunction and fast Li+ conductivity interfaces are developed to regulate the Li+ distribution and the direction of dendrite growth. More importantly{,} the effect of different Li+ concentration gradient frameworks on Li+ deposition behavior was analyzed in detail. Synchrotron X-ray tomography demonstrates that macropores dominate the framework{,} which effectively suppresses the volume change caused by lithium deposition. DFT calculations confirm the high lithiophilicity of γ-Al2O3 and the graphene heterojunction. Synchrotron radiation-based soft X-ray absorption spectroscopy illustrates the fast Li+ conductivity Li–Al–O interface resulting from the shortened Al–O bond distance. Benefiting from the higher Li+ concentration differences during the dissolution process and Li–Al–O interfaces{,} the gradient framework can achieve a high rate performance of ∼40 mV overpotential at 10 mA cm−2 and long cycle stability of ∼1500 h at 1 mA cm−2.

Abstract
Sensors are crucial in the understanding of machines working under high temperatures and high-pressure conditions. Current devices utilize polymeric materials as electrical insulators which pose a challenge in the device’s lifespan. Ceramics, on the other hand, is robust and able to withstand high temperature and pressure. For such applications, a co-fired ceramic device which can provide both electrical conductivity and insulation is beneficial and acts as a superior candidate for sensor devices. In this paper, we propose a novel fabrication technique of complex multi-ceramics structures via 3D printing. This fabrication methodology increases both the geometrical complexity and the device’s shape precision. Structural ceramics (alumina) was employed as the electrical insulator whilst providing mechanical rigidity while a functional ceramic (alumina-doped zinc oxide) was employed as the electrically conductive material. The addition of sintering additives, tailoring the printing pastes’ solid loadings and heat treatment profile resolves multi-materials printing challenges such as shrinkage disparity and densification matching. Through high-temperature co-firing of ceramics (HTCC) technology, dense high quality functional multi-ceramics structures are achieved. The proposed fabrication methodology paves the way for multi-ceramics sensors to be utilized in high temperature and pressure systems in the near future.

Abstract
Bulk hierarchical porous ceramics with unprecedented strength-to-weight ratio and tunable pore sizes across three different length scales are printed by direct ink writing. Such an extrusion-based process relies on the formulation of inks in the form of particle-stabilized emulsions and foams that are sufficiently stable to resist coalescence during printing.