Synthesis and characterization of carboxymethyl cellulose (CMC) from salak-fruit seeds as anode binder for lithium-ion battery

Lithium-ion batteries are most popular battery for applications as portable electrical energy storage. Lithium-ion battery have some advantages compared to other battery such as have large specific energy capacity, light weight and long-life span. One of the components that contribute to the quality of Lithium-ion batteries is the binder material. Carboxymethyl Cellulose (CMC) is one of the most widely used binder materials other than PVDF. CMC can be synthesized from various organic materials such as empty bunches of palm, water hyacinth and salak-fruit seed. In this research, CMC is obtained from waste of salak-fruit seed (Salacca zalacca) and then used as anode binder in lithium-ion battery. The steps of CMC synthesis consist of cellulose isolation from salak-fruit seed, followed by alkalization process, carboxymethylation and finally the purification process. FTIR spectrum of CMC shows the successfully of CMC synthesis, the presence of strong absorption band at 1600 cm-1 and 1438 cm-1 is related to stretching vibration from the carboxyl group (COO-) and carboxyl group as it salts (COO-Na), respectively. The absorption in the region 1321–1400 cm-1 is due to symmetrical deformations of CH2 groups while broad absorption at around 3400 cm-1 is due to the stretching of the hydroxyl groups (-OH). Application CMC as binder of graphite anode with 5wt% CMC shows good surface profile and evenly distributed cavities with conductivity of about 0.815 S/cm.