Boston ivy-inspired natural-rich binder with strong adhesion for advanced silicon-based anodes

The desirable specific theoretical capacity (3579 mAh g−1) of silicon (Si) renders it beneficial as a next-generation anode for lithium-ion batteries (LIBs). However, the significant volume expansion restricts its commercial application. Here, inspired by natural Boston ivy, an efficient and facile strategy to design a three-dimensional (3D)-crosslinked binder for high-performance Si-based anodes enabled by synergizing “Disk” (small molecules) and “Vine” (long chains) is reported. The small molecule branch-like tannic acid (TA) rich in hydroxyl (−OH) groups tends to have multidimensional hydrogen-bonding interactions with the Si surfaces. Meanwhile, the long chains of polysaccharides, such as carboxymethyl cellulose (CMC) and hyaluronic acid (HA), are beneficial for the large-scale bridging of components in an electrode. Moreover, the in-situ cross-linking of TA and polysaccharides can establish a 3D network to release the inner stress of Si particles. Consequently, this cooperation benefits stable slurry, high adhesive strength, and favorable rate performance. Moreover, when over 100 cycles, the Si anode incorporating tannic-carboxymethyl cellulose (TAC) as the binder delivers a high specific capacity of 2782 mAh g−1. Additionally, favorable practicality is demonstrated by the stable operation of a commercial silicon/graphite (Si/Gr) anode and full-cells.