Xuewei Fu

Surface functionalization through advanced skin‐like nanocoating is of great significance due to its tremendous potential in transforming materials technologies. Conventional strategies, including wet‐slurry coatings or vapor depositions, not only involve toxic solvents or expensive/time‐consuming processes, but also lead to weak interfaces. Here, we discover the compelled wetting effects of liquid‐metal (LM) during sponge‐rubbing coating, and propose a strategy of surface in situ compositing (SISC) that combines reactive liquid‐metal and van der Waals (vdW) materials (e.g., graphene and boron nitride) by sequenced sponge‐rubbing. Particularly, the components are in situ composited by the intensive frictional shearing of sponge‐rubbing, forming a robust metal‐conductive skin‐coating with ordered and mechanical interlocking microstructures anchored onto various substrates (e.g., polyimide, PI). For applications, the resultant vdM@PI film has been proven as a high‐performance active composite current collector (ACCC) capable of boosting the energy‐density and safety of batteries, an advanced Joule‐heating material for fast battery thermal‐management, and a photothermal material for efficient solar‐energy conversion.

Composite polymer electrolytes (CPEs) offer a promising solution for all-solid-state lithium-metal batteries (ASSLMBs). However, conventional nanofillers with Lewis-acid–base surfaces make limited contribution to improving the overall performance of CPEs due to their difficulty in achieving robust electrochemical and mechanical interfaces simultaneously. Here, by regulating the surface charge characteristics of halloysite nanotube (HNT), we propose a concept of lithium-ion dynamic interface (Li⁺-DI) engineering in nano-charged CPE (NCCPE). Results show that the surface charge characteristics of HNTs fundamentally change the Li⁺-DI, and thereof the mechanical and ion-conduction behaviors of the NCCPEs. Particularly, the HNTs with positively charged surface (HNTs⁺) lead to a higher Li⁺ transference number (0.86) than that of HNTs⁻ (0.73), but a lower toughness (102.13 MJ m⁻³ for HNTs⁺ and 159.69 MJ m⁻³ for HNTs⁻). Meanwhile, a strong interface compatibilization effect by Li⁺ is observed for especially the HNTs⁺-involved Li⁺-DI, which improves the toughness by 2000% compared with the control. Moreover, HNTs⁺ are more effective to weaken the Li⁺-solvation strength and facilitate the formation of LiF-rich solid–electrolyte interphase of Li metal compared to HNTs⁻. The resultant Li|NCCPE|LiFePO₄ cell delivers a capacity of 144.9 mAh g⁻¹ after 400 cycles at 0.5 C and a capacity retention of 78.6%. This study provides deep insights into understanding the roles of surface charges of nanofillers in regulating the mechanical and electrochemical interfaces in ASSLMBs.

The conformational folding/unfolding behaviors of DNA supercoils serve as a fundamental mechanism governing ultradense bio‐information storage and precise genetic transcription. Mimicking those nanoscale dynamic conformational behaviors for macroscopic materials to achieve unusual functionalities will be of great interest but remains unexplored. Herein, a DNA‐inspired materials evolution paradigm is presented to create multifunctional supercoiled conformational fibers (SCFs) by programmed twisting controlled self‐buckling. Through the programmed twist‐stress modulation, a low‐density polyethylene strip is transformed into high‐performance DNA‐like SCF through a unique multiscale microstructure evolution process. This DNA‐like SCF exhibits five hallmark characteristics unattainable before, including ultra‐large elastic deformability (900 ± 50%), metal‐level mechanical strength (330 ± 30 MPa), unprecedented torsional energy‐storage density (16.1 ± 0.6 kJ kg ⁻¹ ), torsional energy release upon appropriate stimulations, and impact buffering through conformation‐mediated energy‐dissipation. Characterization reveals that these unexpected energy‐related properties mainly are contributed by the multiscale twisting‐reinforced microstructures and conformation mechanics. Potential applications of the SCFs are demonstrated finally by harvest‐and‐storage of wind energy and soft‐landing. The DNA‐like SCFs indicate a general platform for materials evolution with extraordinary mechanics and functions.

The booming Internet of Things will generate diverse requirements for specialized power sources featuring customizable mechanical properties and shapes. However, these features are usually challenging to achieve with traditional batteries. Here, we report the design of self-powered composites (SPCs) by a bioinspired device-to-material integration (DTMI) strategy to break the above shackles. Specifically, commercially cheap small coin cells are employed as functional cell fillers for polymer composites, which are united by bioinspired conductive connections. Meanwhile, the polymer host is 3D printed with a bioinspired configuration to increase the energy density and achieve customizable shapes. The results show that commercial small coin cells (CR927) can work as reinforcement and functional fillers for polymer composites with a high electrochemical compression strength of 158 MPa, as revealed by in situ electrochemical mechanical testing. Via the DTMI strategy, SPCs have been successfully fabricated with either high mechanical strength or stretchability. Enabled by these features, SPCs are further demonstrated to be promising building blocks for self-powered electrical vehicles and wearable electronics. Moreover, a stretchable SPC with slidable cell-connection is demonstrated as a smart sensor for stretching rate due to an electrochemistry–polymer relaxation coupling process. This study may open an avenue for self-powered materials for electrical vehicles, robotics, wearable electronics, and beyond.

Helix-fiber composites (HFCs), which involve wrapping a material around a flexible core, are of interest for intelligent stretchable functional materials or devices. Here, we reveal that mechanical coupling between the core and wrapping plays a critical role in controlling the structure and mechanical properties. Our results show that the mechanical properties of the HFC can be programmed by precisely tuning the mechanical coupling strength among them. Interestingly, the HFC also shows unique pseudo-elastic behavior under large strain due to the mechanical coupling effects. The HFC is demonstrated as an elastic metal conductor, programmable sensor, and finally as an elastic mold for structure transplantation by mechanically decoupling the elastomer core from the helix fiber. The results not only deepen the fundamental understanding of HFCs, but also may promote future structure-properties and fabrication studies on helix-structured functional composite and devices.

To combat severe soil desertification and sandstorms, the application of appropriate hydrogels to dry land/desert is a promising solution to advance sustainable water irrigation and retention, and even realize “intelligent” agriculture. To this end, the development of a hydrogel with stable monitoring functions and good mechanical properties to maintain the swelling capability under soil would be significant for “intelligent” agriculture applications. Herein, we report a robust bio-based hydrogel with excellent mechanical properties and unique fluorescence performance for monitoring irrigation applications. This bio-hydrogel possesses a double cross-linked interpenetrating supramolecular network in a bacterial cellulose (BC) porous matrix, which provides its high tensile/compressive strength (∼0.96/1.3 MPa) and excellent Young's modulus (∼6.67 MPa, vs. 0.01–1.0 MPa for reported agricultural hydrogels), as well as high strength retention after experiencing repeated swelling/drying and long-term compressive processes. Furthermore, the hydrogel displays unique non-traditional fluorescence with excellent stability even under extreme environmental conditions, such as high/low temperature and various organic solvents. The excellent fluorescence characteristics offer the potential to realize “visualized” agricultural irrigation. This study not only provides a distinctive bio-based hydrogel with broadened applications, but also presents new insight to promote the development of sustainable agriculture.

Decoupling the ion motion and segmental relaxation is significant for developing advanced solid polymer electrolytes with high ionic conductivity and high mechanical properties. Our previous work proposed a decoupled ion transport in a novel protein-based solid electrolyte. Herein, we investigate the detailed ion interaction/transport mechanisms through first-principles density functional theory (DFT) calculations in a vacuum space. Specifically, we study the important roles of charged amino acids from proteins. Our results show that the charged amino acids (i.e., Arg and Lys) can strongly lock anions (ClO₄^–). When locked at a proper position (determined from the molecular structure of amino acids), the anions can provide additional hopping sites and facilitate Li⁺ transport. The findings are supported from our experiments of two protein solid electrolytes, in which the soy protein (with plenty of charged amino acids) electrolyte shows much higher ionic conductivity and lower activation energy in comparison to the zein (lack of charged amino acids) electrolyte.