Initiator integrated 3D printing, namely i3DP, was developed by incorporating a vinyl-terminated initiator into UV curable resin to make functional structural materials that enable genetic post-printing surface-initiated modification. Taking advantage of 3D printing and surface-initiated ATRP, the feasible i3DP makes 3D printed complex architectures possible for nearly any desired surface modification for various applications, for example, even pouring water into a sieve was readily achieved.

In this article, we describe a writable particle-free ink for fast fabrication of highly conductive stretchable circuits. The composite ink mainly consists of soluble silver salt and adhesive rubber. Low toxic ketone was employed as the main solvent. Attributed to ultrahigh solubility of silver salt in short-chain ketone and salt-assisted dissolution of rubber, the ink can be prepared into particle-free transparent solution. As-prepared ink has a good chemical stability and can be directly filled into ballpoint pens and use to write on different substrates to form well adhesive silver salt-based composite written traces as needed. As a result of high silver salt loading, the trace can be converted into highly conductive silver nanoparticle-based composites after in situ reduction. Because of the introduction of adhesive elastomeric rubber, the as-formed conductive composite written trace can not only maintain good adhesion to various substrates but also show good conductivity under various deformations. The conductivity of written traces can be enhanced by repeated writing-reduction cycles. Different patterns can be fabricated by either direct handwriting or hand-copying. As proof-of-concept demonstrations, a typical handwriting heart-like circuit was fabricated to show its capability to work under different deformations, and a pressure-sensitive switch was also manufactured to present pressure-dependent change of resistance.

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The prevalence of the Internet of Things (IoT) and wearable electronics create an unprecedented demand for new power sources which are low cost, high performance, and flexible in many application settings. In this paper, a strategy for the scalable fabrication of high-performance, all-solidstate supercapacitors (SCs) is demonstrated using conventional paper and an inkjet printer. Emerging printed electronics technology and low-cost chemical engraving methods are bridged for the first time to construct Cu x O nanosheets, in situ, on the 3D metallized fiber structures. Benefitting from both the "2D Materials on 3D Structures" design and the binder-free nature of the fabricated electrodes, substantial improvements to electrical conductivity, aerial capacitance, and electrochemical performance of the resulting SCs are observed. With the proposed strategy, the fabricated SCs can be seamlessly integrated into any printed circuit, sensors, or artwork; the properties of these SCs can be easily tuned by simple pattern design, fulfilling the increasing demand of highly customized power systems in the IoT and flexible/wearable electronics industries.

Aluminum foil is the predominant cathodic current collector in lithium-based batteries due to the high electronic conductivity, stable chemical/electrochemical properties, low density, and low cost. However, with the development of next-generation lithium batteries, Al current collectors face new challenges, such as the requirement of increased chemical stability at high voltage, long-cycle-life batteries with different electrolyte systems, as well as improved electronic conductivity and adhesion for new electrode materials. In this study, we demonstrate a novel graphene-like carbon (GLC) coating on the Al foil in lithium-based batteries. Various physical and electrochemical characterizations are conducted to reveal the electronic conductivity and electrochemical stability of the GLC-Al foil in both carbonate- and ether-based electrolytes. Full-cell tests, including Li–S batteries and high-voltage Li-ion batteries, are performed to demonstrate the significantly improved cycling and rate performance of batteries with the use of the GLC-Al foil as current collectors. The cell using the GLC-Al foil can greatly reduce the potential polarization in Li–S batteries and can obtain a reversible capacity of 750 mAh g–1 over 100 cycles at 0.5C. Even with high-sulfur-loading cathodes, the Li–S battery at 1C still maintains over 500 mAh g–1 after 100 cycles. In high-voltage Li-ion batteries, the GLC-Al foil significantly improves the high-rate performance, showing an increased retained capacity by over 100 mAh g–1 after 450 cycles at 1C compared to the bare foil. It is believed that the developed GLC-Al foil brings new opportunities to enhance the battery life of lithium-based batteries.