One‐pot synthesis of high‐capacity silicon anodes via on‐copper growth of a semiconducting, porous polymer

Abstract Silicon‐based anodes with lithium ions as charge carriers have the highest predicted theoretical specific capacity of 3579 mA h g−1 (for Li15Si4). 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 semiconductive triazine‐based graphdiyne polymer network is grown around silicon nanoparticles directly on the current collector, a copper sheet. The porous, semiconducting organic framework (1) adheres to the current collector on which it grows via cooperative van der Waals interactions, (2) acts effectively as conductor for electrical charges and binder of silicon nanoparticles via conjugated, covalent bonds, and (3) 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. Key Points We present a Si‐based anode with superior‐performance close to the limits of theoretical capacities with an advantage of factor ×10 over any hitherto produced, commercial electrode system. Our electrodes sustain physical bending without surface reconstruction or crack formation, and heat shocks without loss of capacity and overall cycling performance. The critical, novelty that enables the extraordinary performance increase and durability of our anodes is a class of semi‐conducting porous organic polymers that replaces all conventional additives in battery ink formulations.