Using an organic acid as a universal anode for highly efficient Li-ion, Na-ion and K-ion batteries

Terephthalic acid (H2TP) is initially unveiled to be the first example of organic anodes exhibiting the universal Li-ion, Na-ion and K-ion storage capabilities. In Li-ion half cells, H2TP can deliver the average capacities of similar to 235 mAh g(-1) for 500 cycles; In Na-ion half cells, H2TP is reported to deliver the average capacities of similar to 200 mAh g(-1) for 50 cycles; and in K-ion half cells, H2TP can exhibit the average capacities of similar to 240 mAh g(-1) for 150 cycles. At the same time, the chemical structure and crystal structure of H2TP could be transformed into its related metal salts on the anode side due to the low reduction potential. This work indicates that organic electrode materials should own the universal metal-ion-storage (e.g., Li+, Na+, K+, etc.) capability for their large void room of organic solid/crystal state.