Algae‐Derived Precursors for Sustainable Electrochemical Energy Storage

The simple production and harvesting of algae, along with its lower environmental impact and fewer geopolitical issues, make it a viable precursor for electrochemical energy storage devices. Algae represent a promising biomaterial for electrode materials in electrochemical energy storage devices, including hard carbon, sol–gel‐based anode batteries, sodium batteries, oxygen reduction reaction catalysts in zinc–air batteries, and cathode materials in zinc‐ion and lithium‐ion batteries. Algae‐based batteries are fabricated using methods like pyrolysis, hydrothermal processes, agar‐aided dissolution, electrolysis, annealing, and sol–gel methods. Among these, the sol–gel method using agar to construct refillable hydrogel batteries stands out. Agar's compatibility with acetylene black enhances electrochemical properties and offers the advantage of refill ability, which is challenging in metal‐ion batteries. Algae carbons have demonstrated enhanced specific capacity and cyclic performance, paving the way for their use in both medical and industrial applications. The article reviews the utilization of algae‐based batteries in different industrial and medical pacemaker applications as well as examines the feasibility of the operation of algae‐based batteries synthesized through various parameters and precursors.