Mesoporous TiO

2

-B/anatase microparticles have been

in-situ

synthesized from K

2

Ti

2

O

5

without template. The TiO

2

-B phase around the particle surface accelerates the diffusion of charges through the interface

while the anatase phase in the coremaintains the capacity stability. The heterojunction interface between themain polymorph of anatase and the trace of TiO

2

-B exhibits promising lithiumion battery performance. This trace of 5% (by mass) TiO

2

-B determined by Raman spectra brings the first discharge capacity of thismaterial to 247mA·h·g

-1

giving 20% improvement compared to the anatase counterpart. Stability testing at 1 C reveals that the capacitymaintains at 171mA·h·g

-1

which is better than 162mA·h·g

-1

for single phase anatase or 159 mA·h·g

-1

for TiO

2

-B. The mesoporous TiO

2

-B/anatase microparticles also show superior rate performance with 100 mA·h·g

-1

at 40 C

increased by nearly 25% as compared to pure anatase. This opens a possibility of a general design route

which can be applied to other metal oxide electrode materials for rechargeable batteries an

d supercapacitors.