Conductive composite binder for recyclable LiFePO4 cathode

In order to solve the problem of poor conductivity of traditional LiFePO4 cathode binders, we developed sodium alginate-congo red copolymers (SA-CR) as water-soluble electrically conductive and mechanically robust composite binder. Unlike most other electrically conductive polymer binders, the procedure is straightforward and low-cost to prepare SA-CR binder. Various SA -CR copolymers were prepared with different degree of compounding of CR to investigate the effect of CR on the electrochemical and physical properties of the prepared electrodes. The copolymer whose composition was filled with a mixture of SA and CR at a 3:1 mass ratio showed the best cell performance, due to the well-balanced electrical conductivity and mechanical properties. It exhibited a specific capacity of 118.8 mAh/g at the 100th cycle with 92.1% capacity retention, significantly better than the 108.5 mAh/g of conventional acetylene black electrodes. CR as a conduction-promoting agent in water-soluble composite binder favors the formation of continuous and homogenous conducting bridges throughout the electrode and increases the compaction density of electrode by reducing the conducting agent content of acetylene black and thus the improvement of electrode performance is realized.