Effect of rigidity of porous structure on electrochemical behavior of pristine Li4Ti5O12 microspheres

• Rigid porous framework of Li4Ti5O12 microspheres can be fabricated by mutual molten growth of primary particles.
• Well-confined nanosized tortuous channels are formed inside Li4Ti5O12 microspheres.
• Li4Ti5O12 microspheres with rigid porous structures exhibit greatly enhanced electrochemical performance.

Highly controllable porous architecture is desirable to tailor the physical and chemical properties of functional materials in advanced lithium ion batteries. Here, porous microspheres of spinel lithium titanate (Li4Ti5O12), a promising alternative anode material for lithium ion batteries, are fabricated by mutual molten growth method in a controllable manner. The key role of the rigidity of the porous structure on the performance of the electrode materials in lithium ion batteries is demonstrated. Rigid framework of the materials is formed by second growth of the primary particles that fused together to generate an interconnected nanopore system inside the spheres, leading to better electrolyte diffusion and lower interparticle contact resistance, relative to the non-porous counterpart. The pristine Li4Ti5O12 microspheres with uniform pore distribution and continuous framework exhibit high tap density, remarkable reversible capacity and rate capability, as well as excellent cycling stability. The present method is scalable and may provide a new approach to fabricate other candidate electrode materials for applications that require both high power and high volumetric energy density.