Seaweed─Modification of Si by Natural Nitrogen-Doped Porous Biochar for High-Efficiency Lithium Batteries

Due to the porous structure and high electrical conductivity of carbon materials, lithium-ion batteries (LIBs) frequently employ carbon cladding to modify silicon anodes. However, the high cost and convoluted manufacturing process have prevented widespread use of carbon-based materials. Due to the abundance of seaweed (Gelidium amansii: GAm), there is a developing interest in seaweed's additional uses. We present, for the first time in lithium-ion batteries, the modification of silicon anodes by algal biomass carbon, which was thoroughly analyzed morphologically, structurally, and electrochemically. Seaweed's biomass carbon is porous and highly linked, making it ideal for evenly enclosing silicon nanoparticles and supplying the porous carbon skeleton with sufficient nitrogen after annealing. The Si@ self-encapsulated naturally nitrogen-doped biochar prepared from seaweed composites displayed reversible capacities of 1111.61 mAh g^-1 after 500 cycles at a high current of 1 A g^-1 and 714.08 mAh g^-1 after 1000 cycles at the same current density.