Design and optimization of carbon materials as anodes for advanced potassium-ion storage

With the swift advancement of renewable energy and escalating demands for energy storage, potassium-ion batteries (PIBs) are increasingly recognized as a potent energy storage technology. Various carbon anode materials have been utilized for PIBs anodes owing to their superior K⁺ storage capacity, outstanding cycling performance, elevated capacity, and cost-effectiveness. Therefore, it is imperative to explore and improve carbon anode materials. This review meticulously encapsulates the recent scholarly advancements in carbon anode materials for PIBs. It elucidates the operational mechanisms of carbon anode for PIBs, provides a synopsis of diverse carbon materials, and deliberates on the prevalent challenges, including cycling stability and potassium-ion diffusion rates. Although soft and hard carbon augmented potassium-ion capacities, the expansive surface areas coupled with the large ionic radius of K⁺ pose substantial challenges to their structural design and optimization. Consequently, this review outlines strategic approaches to the design of carbon materials for excellent potassium storage performance, including the expansion of interlayer spacing, modification of morphology, heteroatom doping, structural defect regulation, incorporation of porous structures, and development of carbon–carbon composites. Finally, the challenges and prospective solutions of carbon anode materials for PIBs with superior energy density and cycling stability were proposed, providing a reasonable guidance for regulation design of carbon materials.

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