Porous Zn2Ti3O8@C rods via in situ carbon coating for superior lithium storage capability

Abstract

In situ carbon-coated Zn₂Ti₃O₈ (Zn₂Ti₃O₈@C) porous 1D rods were constructed by using only the residual ethylene glycol and polyvinylpyrrolidone from the raw materials as carbon source precursors under a nitrogen atmosphere. This modification resulted in the transformation of the irregular morphology of Zn₂Ti₃O₈ observed during air calcination into longer rod-like structures. The carbon coating of the rods effectively reduced charge transfer resistance and enhanced the Li⁺ diffusion coefficient of Zn₂Ti₃O₈, leading to improved electrochemical performance. Moreover, this morphological transformation induced significant pseudocapacitive behavior, greatly enhancing the rate capability, cycling stability, and reversible capacity of Zn₂Ti₃O₈. Compared to pure Zn₂Ti₃O₈, the Zn₂Ti₃O₈@C composite exhibited the better electrochemical properties with higher lithium/delithium capacities of 488.8 mAh g⁻¹ (491.3 mAh g⁻¹) at 100 mA g⁻¹ after 180 cycles. These results highlight the effectiveness of the in situ carbon-coating strategy in producing high-performance electrode materials for lithium-ion batteries.