Advances in Organic Anode Materials for Na‐/K‐Ion Rechargeable Batteries

Abstract

Electrochemical energy storage (EES) devices are gaining ever greater prominence in the quest for global energy security. With increasing applications and widening scope, rechargeable battery technology is gradually finding avenues for more abundant and sustainable systems such as Na-ion (NIB) and Kion batteries (KIB). Development of suitable electrode materials lies at the core of this transition. Organic redox-active molecules are attractive candidates as negative electrode materials owing to their low redox potentials and the fact that they can be obtained from biomass. Also, the rich structural diversity allows integration into several solid-state polymeric materials. Research in this domain is increasingly focused on deploying molecular engineering to address specific electrochemical limitations that hamper competition with rival materials. This Minireview aims to summarize the advances in both the electrochemical properties and the materials development of organic anode materials.

Dibenzo[a,e]Cyclooctatetraene‐Functionalized Polymers as Potential Battery Electrode Materials

“…Organic electrode materials for batteries are gaining increasing interest. [ 1 ] Their higher sustainability and easier recycling relative to traditional, metal‐oxide based electrode materials [ 2,3 ] make them attractive for next generation batteries, [ 4–6 ] and they can operate in a variety of battery configurations, including metal anode cells, metal‐ion cells, [ 7–11 ] and full‐organic cells. [ 12,13 ] Organic‐based batteries often operate in dual‐ion configuration.…”

Mechanochemical synthesis of sodium carboxylates as anode materials in sodium ion batteries

“…Overcoming these issues, the field has seen increased interest in the possibility of using organic based electrodes. [16][17][18][19][20][21][22] Several key advantages can be discerned: 1) immense structural flexibility through the wide range of available and synthesizable chemicals; 2) sustainable production of such reagents from biomass; 3) lower environmental impact compared to (transition) metal oxidebased materials with potentially hazardous components.…”

“…41 Coordination polymers of alkali metal ions and carboxylates (lithium, sodium, and potassium salts of carboxylic acids) are an attractive class of materials for anodes in AMIBs. 16,42,43 The carboxylate functionality is redox active as it can undergo a reduction, enabling insertion of additional alkali-metal ions. Stabilization of this negatively charged state is facilitated by the presence of a conjugated π-system in the organic backbone such as aromatic rings or conjugated alkenes.…”

“…Several materials of this type such as sodium terephthalate [44][45][46] have been reported to be suitable active components in negative electrodes. 16,18,47 The preparation of these compounds is typically conducted using corrosive sodium hydroxide as well as large amounts of solvent. Additionally, they usually require up to 24 h of reaction time as well as heating, sometimes under reflux conditions.…”

“…Sodium dicarboxylates have been reported as promising active compounds for anodes of sodium ion batteries (NIBs). 16 Taking inspiration from compounds that have been synthesised using solution-based methods, several dicarboxylic acids were selected as potential candidate reagents (Figure 1). [44][45][46][48][49][50] Besides the carboxylic acid functionality, these compounds have interesting chemical differences in their backbone that should result in different electrochemical behaviour.…”