In Situ N-Doped Carbon Coating on NaTi₂(PO₄)₃ for Aqueous Hybrid-Ion Batteries Mitigating Hydrogen Evolution...

Aqueous Li⁺/Na⁺ hybrid-ion batteries (AIBs) have emerged as a promising alternative to address concerns regarding lithium resource scarcity and the safety issues associated with organic electrolytes. However, the development of NaTi₂(PO₄)₃ (NTP) as a high-performance anode material for AIBs is hindered by intrinsic challenges, including material dissolution and the competitive hydrogen evolution reaction (HER) at the electrode-electrolyte interface. Meanwhile, the scalable synthesis of NTPs remains constrained by the complexity of conventional preparation methods. In this work, the N-doped carbon-coated NaTi₂(PO₄)₃ (NTP@NC) as an advanced AIB anode material is synthesized. The carbon coating effectively suppresses HER and material dissolution while maintaining electrolyte pH stability. Remarkably, the NTP@NC demonstrates a high-capacity retention of 66% after 1000 cycles, and the assembled pouch cell retains stable performance over 300 cycles. The large-scale production of the material is successfully achieved with a batch mass of 4 kg. This work establishes a clear correlation among the microstructure, composition, and electrochemical performance, facilitating the practical development of anode materials for high-safety aqueous battery technologies.