Developing high-performance electrochemical energy storage systems is one of the most prominent pathways to reach the “net zero emission” goal. For that reason, the demand on batteries has increased exponentially in recent years. Indeed, the conventional batteries based on inorganic materials successfully replied to this request so far. On the other hand, since the R&D efforts have been very intense on such compounds either in academic or industrial level, theoretical limits are almost reached for those conventional systems. Moreover, it is predicted that the increased requirement on such inorganic materials (mostly based on lithium derivatives) may lead scarcity of their raw compounds. It is equally important to mention here that most of these inorganic materials are toxic, unsafe, and unsustainable.[1] Therefore, moving out of the comfort zone to discover novel abundant battery components, which can easily be reached without any geographical limitations, is intriguing. In this context, organic electrode materials (OEMs) are interesting alternatives.

Appearance of OEMs was nearly at the same time with their inorganic competitors. Recently, discovery of molecules carrying redox active side groups (e.g., carbonyls) made OEMs highly interesting in the field.[2] Although their leaching during operations due to their high solubility is always highlighted as a major drawback, forming their polymers neutralized this short-coming.[1] Additionally, going one step further from the traditional 1D polymers to high dimensional (hyper)crosslinked (porous) polymeric backbones make the functional moieties more reachable by the counter ions thanks to the high accessible surface area provided by the empty voids (i.e. pores).[3]

Here we present phenothiazine (PTz)-based hypercrosslinked polymers as high performance and low-cost p-type OEMs, which are rare[4] when compared to the n-types. The syntheses were carried out via a facile method, Friedel-Crafts alkylation (i.e. knitting polymerization),[5,6] in between the low-cost commercially available compounds either to form homopolymer of PTz or its random co-polymers with benzene. The increased benzene portion in the reaction resulted in higher crosslinking, therefore, higher accessible surface areas (BET surface areas from 29 to 586 m² g^-1). Although introduction of the redox inactive benzene reduced the theoretical capacity (from 112 to 77 mAh/g), such addition yielded OEMs with enhanced practicability, including increased durability, operationality in higher C-rates, propensity to increase both polymer content and its mass loading in the electrode. In conclusion, the possibility of such trade-off via macromolecular engineering can be a guide to produce advanced materials with high performance and practicability not only for application in batteries but also in complementary electrochemical techniques.