As a new class of materials, tin pyrophosphate stands out due to its high specific capacity and suitable lithium insertion potential. Carbon?coated SnP₂O₇ particles anchored on a carbon framework (SPO/C@C) have been synthesised by an environmentally friendly approach using phytic acid as a phosphorus and carbon source, with polyethylene oxide (PEO) as an additional carbon source. Experimental results show that the addition of extra carbon layer effectively mitigates the volume expansion of the material and reduces the charge transfer resistance, thereby improving the electronic conductivity and the capacitance contribution ratio. That the SPO/C@C sample with 1.36 g of PEO exhibits excellent dispersion and electrochemical performance. At a current density of 0.5 A/g, the discharge specific capacity is 351.3 mA·h/g after 250 cycles, and at a scan rate of 2.0 mV/s, the capacitance contribution ratio is 60.8%.

Tin phosphide (Sn₄P₃) as the anode material for lithium?ion batteries exhibits high theoretical specific capacity (1.255×10³ mA ? h/g). However, the huge volume expansion and particle agglomeration during the charging and discharging processes lead to serious capacity attenuation. The carbon?coated Sn₄P₃?graphene composite (Sn₄P_3?G@C) was successfully prepared by using graphene as the framework and amorphous carbon material as the coating layer. Sn₄P₃?G@C composite shows a high discharge specific capacity of 0.521×10^-3 mA ? h/g after 70 cycles at 0.05 A/g, and the discharge specific capacity of 0.433×10^-3 mA ? h/g can be maintained after 150 cycles at 0.10 A/g. After 300 cycles at 0.50 A/g, the reversible specific capacity of 0.330×10^-3 mA ? h/g can be exhibited. The co?existence of sheet graphene and carbon coating can not only stabilize the structure of Sn₄P₃ and improve the electrical conductivity of the material, but also effectively alleviate the problem of volume expansion and prevent the agglomeration between particles. Sn₄P₃?G@C shows good lithium storage performance.

Li₂ZnTi₃O₈ anodes coated with N?doped carbon from dopamine hydrochloride were synthesized via a high?temperature solid?state method.Some Ti⁴⁺ ions were reduced to Ti³⁺ ions during synthesis,which enabled the co?modification of coating and doping.The modification method can enhance the ion diffusion coefficients and reduce the charge?transfer resistance.In the rate performance tests at 0.5,1.0,1.5,2.0,2.5,3.0 A/g,the specific capacities of N?doped carbon?coated Li₂ZnTi₃O₈(Li₂ZnTi₃O₈@C?N?2) are over 240.0，220.0，210.0，200.0，190.0，180.0 mA ? h/g,respectively.In addition,the electrochemical performance of this material at a low temperature was also studied.The results show that the Li₂ZnTi₃O₈@C?N?2 sample has much higher discharge specific capacities than those of unmodified Li₂ZnTi₃O₈ anode material at 0 ℃.The initial discharge specific capacity is 262.5 mA ? h/g at 0.2 A/g,and the discharge specific capacity of 241.7 mA ? h/g is still obtained after 300 cycles.Even at 1.0 A/g,the discharge specific capacity is kept at 147.4 mA ? h/g after 300 cycles.