NaTi2(PO4)3/C||LiMn2O4 rechargeable battery operating with Li+/Na+-mixed aqueous electrolyte exhibits superior electrochemical performance

Aqueous rechargeable batteries (ARBs) based on migration of two types of shuttle ions not only enrich the battery families but also make it more available for ARBs with operation potential higher than 1.2   V. In this paper, we report on electrochemical properties of ARBs in configuration of NaTi 2 (PO 4 ) 3 /C||LiMn 2 O 4 , i.e. NTP/C||LMO. NTP/C was prepared through a simple and scalable co-precipitation post annealing treatment method and featured with hierarchical structure, high specific surface area, and abundant mesopores. The electrochemical properties of individual anode and cathode were examined in 1   mol   L −1 Li 2 SO 4 , 1   mol   L −1 Na 2 SO 4 , and 0.5   mol   L −1 Li 2 SO 4 /0.5   mol   L −1 Na 2 SO 4 mixed electrolyte, respectively. It is found that NTP/C exhibits superior operation in 1   mol   L −1 Na 2 SO 4 and inferior operation in 1   mol   L −1 Li 2 SO 4 while the situation is contrary for LMO. However, NTP/C||LMO full cells with Li + /Na + -mixed electrolyte exhibit enhanced electrochemical performance, presenting an anode-dependant electrochemical behavior. When operating at 1C, NTP/C||LMO with Li + /Na + -mixed electrolyte can deliver a discharge specific capacity ( C dis ) of 104.6   mA   h   g −1 based on the weight of NTP/C, and a specific energy ( E cell ) of 59.5   W   h   kg −1 with corresponding specific power of 76.8   W   kg −1 based on the total weight of active electrode materials. After 220 cycles at 1C, the C dis and E cell remain 75.7   mA   h   g −1 and 43.0   W   h   kg −1 , respectively.