MXene-integrated cobalt hydroxycarbonate with optimized interfacial architecture for high-performance lithium-ion battery anodes

Abstract

Cobalt hydroxycarbonate (Co 2 (OH) 2 CO 3 ) is a promising anode material for lithium-ion batteries due to its high specific capacity, low cost, and facile synthesis. However, its practical application is limited by poor electronic and ionic conductivities and severe volume expansion (∼300%) during cycling. In this work, these limitations are addressed by integrating flower-like Co 2 (OH) 2 CO 3 with Ti 3 C 2 T x (T x = -OH, -O, -F, etc.) MXene, a highly conductive and mechanically robust two-dimensional material. Structural and spectroscopic analyses confirm the uniform integration of Co 2 (OH) 2 CO 3 with conductive MXene nanosheets and strong interfacial interactions. The incorporation of MXene significantly enhances charge transport, accelerates lithium-ion diffusion, and reduces volume expansion to ∼48%. The optimized composite containing 5 wt% MXene delivers a high reversible capacity of 985 mAh g −1 at 0.1 A g −1 , excellent rate capability, and capacity retention exceeding 100% after 250 cycles. This study highlights the critical role of MXene-enabled interfacial engineering in developing high-performance conversion-type anodes.