One-pot synthesis of high-capacity silicon anodes via on-copper growth of a semi-conducting, porous polymer

Silicon-based anodes with lithium ions as charge carriers have the highest predicted theoretical specific capacity of 3579 mA h g (for LiSi). Contemporary electrodes do not achieve this theoretical value largely because conventional production paradigms rely on the mixing of weakly coordinated components. In this paper, a semi-conductive triazine-based graphdiyne polymer network is grown around silicon nanoparticles directly on the current collector, a copper sheet. The porous, semi-conducting organic framework (i) adheres to the current collector on which it grows via cooperative van der Waals interactions, (ii) acts effectively as conductor for electrical charges and binder of silicon nanoparticles via conjugated, covalent bonds, and (iii) enables selective transport of electrolyte and Li-ions through pores of defined size. The resulting anode shows extraordinarily high capacity at the theoretical limit of fully lithiated silicon. Finally, we combine our anodes in proof-of-concept battery assemblies using a conventional layered Ni-rich oxide cathode.

Sustainably closed loop recycling of hierarchically porous polymer microbeads for efficient removal of cationic dyes

Herein, we designed and fabricated a hierarchically porous crosslinked polymeric microbead (PCP) with high density of functional groups for selective adsorption of cationic dyes from water. On account of...

Transparent porous polymer sheets for efficient product separation in solar water splitting

Efficient product separation is an essential requirement for the safe operation and implementation of solar water splitting devices. Ion exchange membranes are typically used, but for a device that requires...

Precise fabrication of porous polymer frameworks using rigid polyisocyanides as building blocks: from structural regulation to efficient iodine capture

Macroporous polymer frameworks with a tunable pore size were readily prepared using 4-arm rod-like polymers as building blocks. They showed excellent iodine capture performance with very high efficiency (1 minute) and high capacity (574%).

Layer-by-Layer Electrode Fabrication for Improved Performance of Porous Polyimide-Based Supercapacitors

Nanoporous polymers are becoming increasingly interesting materials for electrochemical applications, as their large surface areas with redox-active sites allow efficient adsorption and diffusion of ions. However, their limited electrical conductivity remains a major obstacle in practical applications. The conventional approach that alleviates this problem is the hybridisation of the polymer with carbon-based additives, but this directly prevents the utilisation of the maximum capacity of the polymers. Here, we report a layer-by-layer fabrication technique where we separated the active (porous polymer, top) layer and the conductive (carbon, bottom) layer and used these “layered” electrodes in a supercapacitor (SC). Through this approach, direct contact with the electrolyte and polymer material is greatly enhanced. With extensive electrochemical characterisation techniques, we show that the layered electrodes allowed a significant contribution of fast faradic surface reactions to the overall capacitance. The electrochemical performance of the layered-electrode SC outperformed other reported porous polymer-based devices with a specific gravimetric capacitance of 388 F·g−1 and an outstanding energy density of 65 Wh·kg−1 at a current density of 0.4 A·g−1. The device also showed outstanding cyclability with 90% of capacitance retention after 5000 cycles at 1.6 A·g−1, comparable to the reported porous polymer-based SCs. Thus, the introduction of a layered electrode structure would pave the way for more effective utilisation of porous organic polymers in future energy storage/harvesting and sensing devices by exploiting their nanoporous architecture and limiting the negative effects of the carbon/binder matrix.