Lightweight yet strong cellular structural materials have long been sought for varied engineering applications due to the outstanding performance, and have been existing in numerous nature’s designs such as wood, bone, and honeycomb. Cellulose is considered an ideal building block for such structure due to its natural abundance, low density, and high mechanical properties derived from the hydrogen bonded crystalline structure. However, restructuring pristine cellulose into 3D architectures with outstanding mechanical properties has always been a challenge. Here, a lightweight (∼90 mg/cm³) and super-strong (16.6 MPa compressive Young’s modulus) honeycomb structure is constructed by 3D printing of all-cellulose ink. The 3D printed all-cellulose structure demonstrates switchable high elasticity (to withstand varied repetitive elastic deformation) at the wet state and high rigidity (to support over 15,800 of its own weight) at dry state. Such superb printing and mechanical properties can be ascribed to the controlled dissolution and regeneration of cellulose, as well as shear induced cellulose alignment during printing. In addition, the 3D printed all-cellulose honeycomb structure demonstrates good thermal insulation properties after filling with cellulose nanofibrils aerogel.

长期以来，由于其出色的性能，人们一直在寻求轻质而坚固的蜂窝结构材料，以用于各种工程应用，并且已经存在于许多自然设计中，例如木材，骨头和蜂窝。纤维素由于其天然丰度，低密度和源自氢键合晶体结构的高机械性能，因此被认为是此类结构的理想构建基块。然而，将原始纤维素重组为具有出色机械性能的3D结构一直是一个挑战。这里是轻量级的（〜90 mg / cm ³）和超强（16.6 MPa压缩杨氏模量）蜂窝结构是通过全纤维素墨水的3D打印构造的。3D打印的全纤维素结构在潮湿状态下显示出可切换的高弹性（以承受各种重复的弹性变形），在干燥状态下显示出高刚性（以支撑超过15800的自重）。这种优异的印刷和机械性能可以归因于纤维素的受控溶解和再生，以及在印刷过程中剪切诱导的纤维素排列。此外，3D打印的全纤维素蜂窝结构在填充纤维素纳米原纤维气凝胶后显示出良好的隔热性能。