Summary In this paper, a systematic method has been developed to produce highly flexible and robust graphene/LiMn2O4 (G/LMO) and graphene/LiCr0.05Mn1.95O4 (G/LCMO) free‐standing composite cathode electrodes with increased specific capacity and improved electrochemical capability. Spinel LMO nanorods are synthesized by calcination method followed by a hydrothermal reaction technique. As‐synthesized nanorods were then embedded in a graphene layer which will in turn serve as a self‐standing binder‐free cathode electrode. Spinel LMO and LCMO nanorods with a length of 600 nm and width of 50 nm were then homogenously entrapped and distributed within the layers of conductive graphene structure. This hybrid structure will help to eliminate the use of heavy metal current collectors and electrically resistant binders or even conductive additives. A discharge capacity of 114.5 mAh g−1 is obtained after first cycle and %72 capacity retention is obtained after 250 cycles from G/LCMO freestanding samples. The enhancement in the electrochemical properties is due to the unique freestanding structure of the cathode electrodes.

Summary In this paper, nanosized Ni3Sn4 nanoparticles were synthesized by chemical reduction technique. A facile strategy is also developed to synthesize the yolk‐shell Ni3Sn4 nanoparticles decorated between the layers of multilayer graphene to obtain high‐capacity, long service life with comparable cost Li‐ion batteries. Ni3Sn4 nanoparticles in the form of yolk‐shell morphology were synthesized between 30 and 130 nm in size and homogeneously anchored on graphene layers as spacers preventing the layers merging after vacuum filtration. The characterization of the as‐synthesized composite electrodes was performed by scanning electron microscopy and X‐ray diffraction methods. As an anode electrode, yolk‐shell Ni3Sn4/graphene composite electrodes revealed a stable capacity of 324.5 mAh g−1 after 250 cycles, indicating that the composites might have a promising future application in Li‐ion batteries. The results have shown that unique yolk‐shell Ni3Sn4/graphene hybrid composite structure shows extraordinary electrochemical performance with superior reversible capacity and improved cyclic performance, indicating that the stacking of the active electrode nanoparticles between the graphene layers is a good method for maximum specific capacity outputs.

Significant climate change and variable fossil energy prices are forcing us to minimize fossil fuel consumption and develop innovative energy conversion and storage systems capable of reducing carbon dioxide emissions. Batteries are the most common form of alternative energy systems, and cathode materials are critical for their performance. Their low-rate performance and short lifespan severely hamper the efficiency of cathode materials. The adoption of nanotechnology is essential to improve the cathode life cycle and maintain capacity. Conventional synthetic techniques face serious problems in producing complex nanomaterials with precise design, high efficiency, and long life. Recent efforts have been made to utilize bio-inspired materials in a variety of applications, emphasizing the importance of biomimetics due to their unique advantages and excellent properties. This review examines the synthesis mechanism, properties, and advances of bioinspired materials in the production of nanomaterials in order to pave the way for the future study of rechargeable batteries. Subsequently, the solutions and problems encountered by cathode materials in the main categories of secondary rechargeable batteries are addressed. The aim of this study is to alert scientists toward this promising development trend in bio-inspired battery materials.